Author name code: wang-jingxiu ADS astronomy entries on 2022-09-14 =author:"Wang, Jing-Xiu" OR =author:"Wang, J.-X." OR =author:"Wang, J.X." ------------------------------------------------------------------------ Title: Characterization of Kepler targets based on medium-resolution LAMOST spectra analyzed with ROTFIT Authors: Frasca, A.; Molenda-Żakowicz, J.; Alonso-Santiago, J.; Catanzaro, G.; De Cat, P.; Fu, J. N.; Zong, W.; Wang, J. X.; Cang, T.; Wang, J. T. Bibcode: 2022A&A...664A..78F Altcode: 2022arXiv220504757F
Aims: In this work we present the results of our analysis of 16 300 medium-resolution LAMOST spectra of late-type stars in the Kepler field with the aim of determining the stellar parameters, activity level, lithium atmospheric content, and binarity.
Methods: We have used a version of the code ROTFIT specifically developed for the LAMOST medium-resolution spectra to determine stellar parameters via the adoption of a grid of spectra of real stars. We provide a catalog with the atmospheric parameters (Teff, log g, and [Fe/H]), radial velocity (RV), and projected rotation velocity (v sin i). For cool stars (Teff ≤ 6500 K), we also calculated the Ha and Li Iλ6708 equivalent width, which are important indicators of chromospheric activity and evolutionary stage, respectively.
Results: From the sample of 16 300 spectra, we have derived the RV and atmospheric parameters for 14 300 spectra of 7443 stars. Literature data (mainly from high- or medium-resolution spectra) were used for a quality control of the results and to assess the accuracy of the derived parameters. The Teff and log g values are in good agreement with the literature, although their distribution displays some clustering effects, which may be the result of the nonuniform distribution of the templates in the parameter space. The most relevant differences are found for [Fe/H], which appears to be overestimated for metal-poor stars; this overestimation is also likely due to the template grid. We propose a relation to correct the [Fe/H] values derived with ROTFIT. We were able to identify interesting objects, such as double-lined binaries, stars with variable RVs, lithium-rich giants, and emission-line objects. Based on the Hα flux, we found 327 active stars. We were able to detect the Li Iλ6708 line and measure its equivalent width for 1657 stars, both giants and stars on the main sequence. Regarding the latter, we performed a discrete age classification based on the atmospheric lithium abundance and the upper envelopes of a few open clusters. Among the giants, we found 195 Li-rich stars, 161 of which are reported here for the first time. No relationship is found between stellar rotation and lithium abundance, which allows us to rule out merger scenarios as the predominant explanation of the enrichment of Li in our sample. The fraction of Li-rich giants, ≈ 4%, is higher than expected.

Full Tables C.2, C.3, 2, 3, and 4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/664/A78 Title: The Nonuniformity of Poleward Flux Transport on the Solar Surface: A Statistical Method Applied to Solar Cycles 21-24 Authors: Wang, Zi-Fan; Jiang, Jie; Wang, Jing-Xiu Bibcode: 2022ApJ...930...84W Altcode: 2022arXiv220316119W The poleward migration of the active regions' magnetic flux on the solar surface plays an important role in the development of the large-scale field development, especially the polar-field reversal, which is a key process in the Babcock-Leighton-type solar dynamos. The poleward flux transport is nonuniform, centered around poleward surges as suggested by previous observations. The strong, long-lasting surges are related to activity complexes, and often result in violent polar-field reversal. However, the nonuniformity of poleward flux transport has not been evaluated quantitatively. We propose a statistical method to analyze the poleward flux transport during solar cycles 21-24 by considering the frequency distributions of the magnetic field at latitudes of poleward surges occurring during solar cycles. The nonuniformity is quantified as the kurtosis statistics representing the tailedness of the distributions. We test the method on results of surface flux transport simulations, and apply it to WSO, National Solar Observatory, MWO, and HMI data. We confirm that the poleward surges are of significance during solar cycles 21-24 in general. The kurtosis within a solar cycle is affected by different latitudes of the magnetic field and different data sources. The southern hemisphere of cycle 24 exhibits the largest kurtosis, agreeing with the super-surge concept from previous work. The significant nonuniformity of poleward flux transport originates from the nonrandomness of active regions, which favors the activity complexes as the origin of poleward surges. Title: VizieR Online Data Catalog: Kepler targets class based on LAMOST spectra (Frasca+, 2022) Authors: Frasca, A.; Molenda-Zakowicz, J.; Alonso-Santiago, J.; Catanzaro, G.; De Cat, P.; Fu, J. N.; Zong, W.; Wang, J. X.; Cang, T.; Wang, J. T. Bibcode: 2022yCat..36640078F Altcode: Spectral type, average atmospheric parameters (Teff, logg, and [Fe/H]), radial velocity (RV) and projected rotational velocity (vsini) are quoted in Table 2 for 7443 stars.

Table 3 reports the H-alpha equivalent width and flux at the stellar surface for 327 targets.

Table 4 reports the LiI-6708 equivalent width and lithium abundance for 1657 targets.

(5 data files). Title: Response of the Fe Kα line emission to the X-ray continuum variability in the changing-look active galactic nucleus NGC 1566 Authors: Liang, W. C.; Shu, X. W.; Wang, J. X.; Tan, Y.; Zhang, W. J.; Sun, L. M.; Jiang, N.; Dou, L. M. Bibcode: 2022JHEAp..33...20L Altcode: 2022arXiv220111050L NGC 1566 is a changing look AGN known to exhibit recurrent X-ray outbursts with each lasting for several years. The most recent X-ray outburst is observed on 2018, with a substantial increase of 2-10 keV flux by a factor of ∼24 than the historical minimum. We re-analyze the XMM-Newton and NuSTAR observations covering the pre-outburst, outburst and post-outburst epochs, and confirm the discovery of the broad feature in the ∼5-7 keV band during the period of outburst that could be interpreted as a relativistic Fe Kα emission line. Our analysis suggests that its flux has increased in tandem with the 2-10 keV continuum, making it the second changing look AGN in which the broad Fe Kα line responds to the X-ray continuum variability. This behavior strongly supports the idea that X-rays originates in a corona above the accretion disk, and disk reflection produces the relativistic Fe Kα line. In addition, we find the response of narrow Fe Kα emission line to the changes in the X-ray continuum on a time-scale as short as four months, allowing to put the location of line-emitting region at <0.1 pc, comparable to the size of optical BLR. By comparing to the changing look AGN NGC 2992, the Fe Kα variation rate (the ratio of Fe Kα variation to luminosity variation) in NGC 1566 appears greater, which could be possibly explained by larger amount of gas or Fe abundance responsible for producing the Fe Kα line for the latter. The strength of variable broad Fe Kα line as well as the soft X-ray excess emission appears to be correlated with the accretion rate, which could be explained as due to the state transition associated with the changing-look phenomenon. Title: A Dynamo-Based Prediction of Solar Cycle 25 Authors: Guo, Wei; Jiang, Jie; Wang, Jing-Xiu Bibcode: 2021SoPh..296..136G Altcode: 2021arXiv210801412G The solar activity cycle varies in amplitude. The last Solar Cycle 24 is the weakest in the past century. Sun's activity dominates Earth's space environment. The frequency and intensity of Sun's activity follow the solar cycle. Hence there are practical needs to know the amplitude of the upcoming Solar Cycle 25. Dynamo-based solar cycle predictions not only provide forecasts, but also offer an effective way to evaluate our understanding of the solar cycle. In this article we apply the method of the first successful dynamo-based prediction developed for Solar Cycle 24 to predict Solar Cycle 25, so that we can verify whether the previous success is repeatable. The prediction shows that Solar Cycle 25 would be about 10% stronger than Solar Cycle 24 with an amplitude of 126 (international sunspot number Version 2.0). The result suggests that Solar Cycle 25 will not be the beginning of a Maunder-like grand solar minimum as suggested by some publications. The solar behavior in about four to five years will confirm whether the prediction method captures the key mechanism for solar cycle variability, which is the polar field around the cycle minimum in our model. Title: Algebraic quantification of an active region contribution to the solar cycle Authors: Wang, Zi-Fan; Jiang, Jie; Wang, Jing-Xiu Bibcode: 2021A&A...650A..87W Altcode: 2021arXiv210404307W Context. The solar dipole moment at cycle minimum is considered to be the most reliable precursor with which to determine the amplitude of the subsequent cycle. Numerical simulations of the surface flux transport (SFT) model are widely used to effectively predict the dipole moment at cycle minimum. An algebraic method was recently proposed to quickly predict the contribution of an active region (AR) to the axial dipole moment at cycle minimum instead of SFT simulations. The method assumes a bipolar magnetic region (BMR) configuration of ARs, however most ARs are asymmetric in configuration of opposite polarities, or have more complex configurations. Such ARs evolve significantly differently from those of BMR approximations.
Aims: We propose a generalized algebraic method to describe the axial dipole contribution of an AR with an arbitrary configuration, and evaluate its effectiveness compared to the BMR-based method.
Methods: We employ mathematical deductions to obtain the generalized method. We compare the results of the generalized method with SFT simulations of observed ARs, artificially created BMRs, and ARs with more complex configurations. We also compare the results with those from the BMR-based method.
Results: The generalized method is equivalent to the SFT model, and precisely predicts the contributions of ARs to the dipole moment, but has a much higher computational efficiency. Although the BMR-based method has similar computational efficiency to the generalized method, it is only accurate for symmetric bipolar ARs. The BMR-based method systematically overestimates the dipole contributions of asymmetric bipolar ARs, and randomly miscalculates the contributions of more complex ARs.
Conclusions: The generalized method provides a quick and precise quantification of the contribution of an AR to solar cycle evolution, which paves the way for application in physics-based solar cycle predictions. Title: Homologous Microflares with Mass Ejection and Plasma Heating on the Quiet Sun Authors: Jin, C. L.; Zhou, G. P.; Wang, J. X. Bibcode: 2021ApJ...914L..35J Altcode: Study of microflares on the quiet Sun is extremely important in learning the physics of both solar flare and atmospheric heating. Here, for the first time, we report the detailed observations of two homologous microflares from Atmospheric Imager Assembly (AIA) images and Heliospheric Magnetic Imager magnetograms in a very quiet region. The two microflares are observed clearly in the extreme ultraviolet and faintly in the ultraviolet in AIA images. They have an area of 59 Mm2 and 46 Mm2, and a duration of 25 minutes and 22 minutes. The magnetic cancellation continuously takes place during the microflares, and the magnetic flux decrease is apparent, with a value of 4 1018 Mx. The obvious mass ejections are observed during the microflares, and dimming occurs during and after the microflares. The velocity of mass ejection is up to 160 km s1. For the two microflares, the time of peak intensity in 30.4 nm precedes that of the coronal peak emission, up to 2.43.3 minutes. Their thermal energy is estimated to be 1.3 1027 erg and 2.5 1026 erg, respectively, which heats the corona up to 5.8 MK and 2.8 MK. There are many similarities of microflares on the quiet Sun to major flares in the active regions. Title: Physical Parameters of the Eclipsing Binary System EPIC 202060577 Authors: Zhao, S. J.; Fu, J. N.; Wang, J. T.; Li, C. Q.; Wang, J. X.; Zong, W. K. Bibcode: 2021AcASn..62...23Z Altcode: EPIC 202060577 is an eclipsing binary system containing a B-type primary star. From the K2 photometry, 45 secondary minimal times were obtained. The orbital period is determined to be 1.019648 days and the epoch formula is derived. Based on LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) spectra, the ROTFIT program is used to obtain spectral class, effective temperature, metal abundance and surface gravity of the primary star, and calculate the radial velocities. Through the PHOEBE (Physics Of Eclipsing Binaries) modeling program and emcee (Affine Invariant Markov chain Monte Carlo Ensemble Sampler) fitting program, a solution of the orbital parameters is obtained and the influence of Rossiter-McLaughlin effect on the radial velocity curve is analyzed. The final solution shows that EPIC 202060577 is a detached eclipsing binary system with mass ratio q=0.11, the spectral class of the primary star is B2/3. The mass, radius and effective temperature of the primary and secondary stars are M_1=12.56M_{⊙} and M_2= 1.39M_{⊙}, R_1=4.58R_{sun} and R_2=1.85R_{rm sun}, T_1=18979 K and T_2=8710 K, respectively, here M_{⊙} and R_{sun} are the solar mass and solar radius. According to the physical parameters, the evolutionary phase of EPIC 202060577 is discussed. Title: Activity Complexes and a Prominent Poleward Surge during Solar Cycle 24 Authors: Wang, Zi-Fan; Jiang, Jie; Zhang, Jie; Wang, Jing-Xiu Bibcode: 2020ApJ...904...62W Altcode: 2020arXiv200912483W Long-lasting activity complexes (ACs), characterized as a series of closely located, continuously emerging solar active regions (ARs), are considered generating prominent poleward surges from observations. The surges lead to significant variations of the polar field, which are important for the modulation of solar cycles. We aim to study a prominent poleward surge during solar cycle 24 on the southern hemisphere, and analyze its originating ACs and the effect on the polar field evolution. We automatically identify and characterize ARs based on synoptic magnetograms from the Solar Dynamics Observatory. We assimilate these ARs with realistic magnetic configuration into a surface flux transport model, and simulate the creation and migration of the surge. Our simulations well reproduce the characteristics of the surge and show that the prominent surge is mainly caused by the ARs belonging to two ACs during Carrington rotations 2145-2159 (2013 December-2015 January). The surge has a strong influence on the polar field evolution of the southern hemisphere during the latter half of cycle 24. Without the about one-year-long flux emergence in the form of ACs, the polar field around the cycle minimum would have remained at a low level and even reversed to the polarity at cycle 23 minimum. Our study also shows that the long-lived unipolar regions due to the decay of the earlier emerging ARs cause an intrinsic difficulty of automatically identifying and precisely quantifying later emerging ARs in ACs. Title: VizieR Online Data Catalog: Sun active regions from 1976-2017 (Jiang+, 2019) Authors: Jiang, J.; Song, Q.; Wang, J. -X.; Baranyi, T. Bibcode: 2020yCat..18710016J Altcode: The Debrecen Photoheliographic Data (DPD) sunspot catalog (Baranyi+, 2016SoPh..291.3081B) is the most detailed and user-friendly catalog at present. It provides the area and position data for each observable sunspot and sunspot groups on a daily basis along with images of sunspot groups, full-disk scans, and magnetograms starting from 1974 to the present.

The Geostationnary Operational Environmental Satellites (GOES) X-ray data are available from 1975 September onwards. We select ARs that are larger than 800{micro}Hem from the beginning of 1976 to the end of 2017. The 567 ARs that satisfy this requirement are singled out as our samples.

(1 data file). Title: Accurate focusing technology for the coronal images Authors: Zhang, X. F.; Liu, Y.; Li, X. B.; Song, T. F.; Zhao, M. Y.; Wang, J. X. Bibcode: 2019SPIE11116E..1DZ Altcode: Optical imaging has been widely used in many fields as a tool for acquiring images, which can be used in microscopic observation, medical analysis, remote sensing, and astronomical observation. In the field of astronomical observations, it is very important to adjust the focus of the coronagraph. Due to the significant differences of the intensity between the corona and the solar photosphere, the ground-based coronagraph usually adopt an occulter, which is a little larger than the solar disk, to shield the light from the solar photosphere. In absence of the Sun as reference, focusing of the coronagraph is much harder than usual optical system. For the ground-based coronagraph, we developed a method of focusing using the solar disk image behind this disk occulter. Based on a series of images collected by shifting the center of the solar disk, we extract edge information of the solar disk and use the edge gradient algorithm to fit the focal length. This method can reduce the error of manual focusing. We can precisely find out the coronagraph focal point and obtain a clear coronal image, which lays a foundation for the technical support about remote control system of the coronagraph. Title: Magnetic flux participation in solar surface magnetism during solar cycle 24 Authors: Jin, Chun-Lan; Wang, Jing-Xiu Bibcode: 2019RAA....19...69J Altcode: This study aims at investigating surface magnetic flux participation among different types of magnetic features during solar cycle 24. State-of-the-art observations from SDO/HMI and Hinode/SOT are combined to form a unique database in the interval from April 2010 to October 2015. Unlike previous studies, the statistics presented in this paper are feature-detection-based. More than 20 million magnetic features with relatively large scale, such as sunspot/pore, enhanced and quiet networks, are automatically detected and categorized from HMI observations, and the internetwork features are identified from SOT/SP observations. The total flux from these magnetic features reaches 5.9×1022 Mx during solar minimum and 2.4×1023 Mx in solar maximum. Flux occupation from the sunspot/pore region is 29% in solar maximum. Enhanced and quiet networks contribute 18% and 21% flux during the solar minimum, and 50% and 9% flux in the solar maximum respectively. The internetwork field contributes over 55% of flux in the solar minimum, and its flux contribution exceeds that of sunspot/pore features in the solar maximum. During the solar active condition, the sunspot field increases its area but keeps constant flux density of about 150G, while the enhanced network follows the sunspot number variation showing increasing flux density and area, but the quiet network displays decreasing area and somewhat increasing flux density of about 6%. The origin of the quiet network is not known exactly, but is suggestive of representing the interplay between mean-field and local dynamos. The source, magnitude and possible importance of ‘hidden flux’ are discussed in some detail. Title: A magnetar-powered X-ray transient as the aftermath of a binary neutron-star merger Authors: Xue, Y. Q.; Zheng, X. C.; Li, Y.; Brandt, W. N.; Zhang, B.; Luo, B.; Zhang, B. -B.; Bauer, F. E.; Sun, H.; Lehmer, B. D.; Wu, X. -F.; Yang, G.; Kong, X.; Li, J. Y.; Sun, M. Y.; Wang, J. -X.; Vito, F. Bibcode: 2019Natur.568..198X Altcode: 2019arXiv190405368X Mergers of neutron stars are known to be associated with short γ-ray bursts1-4. If the neutron-star equation of state is sufficiently stiff (that is, the pressure increases sharply as the density increases), at least some such mergers will leave behind a supramassive or even a stable neutron star that spins rapidly with a strong magnetic field5-8 (that is, a magnetar). Such a magnetar signature may have been observed in the form of the X-ray plateau that follows up to half of observed short γ-ray bursts9,10. However, it has been expected that some X-ray transients powered by binary neutron-star mergers may not be associated with a short γ-ray burst11,12. A fast X-ray transient (CDF-S XT1) was recently found to be associated with a faint host galaxy, the redshift of which is unknown13. Its X-ray and host-galaxy properties allow several possible explanations including a short γ-ray burst seen off-axis, a low-luminosity γ-ray burst at high redshift, or a tidal disruption event involving an intermediate-mass black hole and a white dwarf13. Here we report a second X-ray transient, CDF-S XT2, that is associated with a galaxy at redshift z = 0.738 (ref. 14). The measured light curve is fully consistent with the X-ray transient being powered by a millisecond magnetar. More intriguingly, CDF-S XT2 lies in the outskirts of its star-forming host galaxy with a moderate offset from the galaxy centre, as short γ-ray bursts often do15,16. The estimated event-rate density of similar X-ray transients, when corrected to the local value, is consistent with the event-rate density of binary neutron-star mergers that is robustly inferred from the detection of the gravitational-wave event GW170817. Title: Multiple Magnetic Reconnections Driven by a Large-scale Magnetic Flux Rope Authors: Zhou, G. P.; Tan, C. M.; Su, Y. N.; Shen, C. L.; Tan, B. L.; Jin, C. L.; Wang, J. X. Bibcode: 2019ApJ...873...23Z Altcode: Magnetic flux ropes (MFRs), as the most probable core structure of solar eruptive activity, remain mysterious on their origination, magnetic environment, and erupting mechanisms. Here, we newly identify a large-scale hot channel MFR, named “MFR3”, that connects an anti-Hale active region (AR) 11429 and a normal AR 11430 on 2012 March 7 based on multi-wavelength observations. An oscillation is first detected at the top of MFR3 during 00:10-00:30 UT as triggered by an X5.4 flare-related eruption of an MFR (named “MFR1” here) in AR 11429. Then, after a quiet period of ∼20 minutes at around 00:52 UT, external magnetic reconnection (EMR) occurred above MFR3 manifested by not only bidirectional outflow in extreme ultraviolet images, but also microwave quasi-periodic pulsation in broadband radio spectral observations for the first time. With the occurrence of EMR, the large-scale MFR3 quickly erupted at 01:01 UT and triggered an X1.3 flare, which is related to the eruption of the other MFR (named “MFR2” here) in AR 11429 at 01:05 UT. The erupting MFR3 and MFR2 appeared successively in the same associated halo coronal mass ejection (CME) as two different core structures. The identification of the large-scale MFR3 between two separated ARs and its complex activity may shed new light on our understanding of the initiation mechanism of a CME. Further work should lay emphasis on how a large-scale MFR3 forms in the solar atmosphere. Title: Different Contributions to Space Weather and Space Climate from Different Big Solar Active Regions Authors: Jiang, Jie; Song, Qiao; Wang, Jing-Xiu; Baranyi, Tünde Bibcode: 2019ApJ...871...16J Altcode: 2019arXiv190100116J The purpose of this paper is to show that large active regions (ARs) with different magnetic configurations have different contributions to short-term and long-term variations of the Sun. As a case study, the complex δ-type AR 12673 and the simple β-type AR 12674 are investigated in detail. Since the axial dipole moment at cycle minimum determines the amplitude of the subsequent cycle and space climate, we have assimilated the individual observed magnetic configurations of these two ARs into a surface flux transport model to compare their contributions to the axial dipole moment D. We find that AR 12673 has a significant effect on D at the end of the cycle, making it weaker because of abnormal and complicated magnetic polarities. An initial strongly positive D ends up with a strongly negative value. The flare-poor AR 12674 has a greater contribution to the long-term axial dipole moment than the flare-rich AR 12673. We then carry out a statistical analysis of ARs larger than 800 μHem from 1976 to 2017. We use the flare index FI and define an axial dipole moment index DI to quantify the effects of each AR on space weather and space climate, respectively. Whereas the FI has a strong dependence on the magnetic configuration, the DI shows no such dependence. The DI is mainly determined by the latitudinal location and the latitudinal separation of the positive and negative magnetic fluxes of the ARs. Simple ARs have the same possibility as complex ARs to produce big DI values affecting space climate. Title: Variability-selected Low-luminosity Active Galactic Nuclei Candidates in the 7 Ms Chandra Deep Field-South Authors: Ding, N.; Luo, B.; Brandt, W. N.; Paolillo, M.; Yang, G.; Lehmer, B. D.; Shemmer, O.; Schneider, D. P.; Tozzi, P.; Xue, Y. Q.; Zheng, X. C.; Gu, Q. S.; Koekemoer, A. M.; Vignali, C.; Vito, F.; Wang, J. X. Bibcode: 2018ApJ...868...88D Altcode: 2018arXiv181009465D In deep X-ray surveys, active galactic nuclei (AGNs) with a broad range of luminosities have been identified. However, cosmologically distant low-luminosity AGN (LLAGN, {L}{{X}}≲ {10}42 erg s-1) identification still poses a challenge because of significant contamination from host galaxies. Based on the 7 Ms Chandra Deep Field-South (CDF-S) survey, the longest-timescale (∼17 years) deep X-ray survey to date, we utilize an X-ray variability selection technique to search for LLAGNs that remain unidentified among the CDF-S X-ray sources. We find 13 variable sources from 110 unclassified CDF-S X-ray sources. Except for one source that could be an ultraluminous X-ray source, the variability of the remaining 12 sources is most likely due to accreting supermassive black holes. These 12 AGN candidates have low intrinsic X-ray luminosities, with a median value of 7 × 1040 erg s-1. They are generally not heavily obscured, with an average effective power-law photon index of 1.8. The fraction of variable AGNs in the CDF-S is independent of X-ray luminosity and is only restricted by the total number of observed net counts, confirming previous findings that X-ray variability is a near-ubiquitous property of AGNs over a wide range of luminosities. There is an anticorrelation between X-ray luminosity and variability amplitude for high-luminosity AGNs, but as the luminosity drops to ≲1042 erg s-1, the variability amplitude no longer appears dependent on the luminosity. The entire observed luminosity-variability trend can be roughly reproduced by an empirical AGN variability model based on a broken power-law power spectral density function. Title: A unique distant submillimeter galaxy with an X-ray-obscured radio-luminous active galactic nucleus Authors: Shu, X. W.; Xue, Y. Q.; Liu, D. Z.; Wang, T.; Han, Y. K.; Chang, Y. Y.; Liu, T.; Huang, X. X.; Wang, J. X.; Zheng, X. Z.; da Cunha, E.; Daddi, E.; Elbaz, D. Bibcode: 2018A&A...619A..76S Altcode: 2018arXiv180900318S
Aims: We present a multiwavelength study of an atypical submillimeter galaxy, GH500.30, in the GOODS-North field, with the aim to understand its physical properties of stellar and dust emission, as well as the central active galactic nucleus (AGN) activity. Although it is shown that the source is likely an extremely dusty galaxy at high redshift, its exact position of submillimeter emission is unknown.
Methods: We use NOEMA observation at 1.2 mm with subarcsecond resolution to resolve the dust emission, and precisely localize the counterparts at other wavelengths, which allows us to better constrain its stellar and dust spectral energy distribution (SED) as well as redshift. We carry out the new near-infrared (NIR) photometry of GH500.30 observed with HST, and perform panchromatic SED modelling from ultraviolet (UV)/optical to submillimeter. We derive the photometric redshift using both NIR and far-infrared (FIR) SED modeling, and place constraints on the stellar and dust properties such as stellar mass, age, dust attenuation, IR luminosity, and star-formation rate (SFR). The AGN properties are inferred from the X-ray spectral analysis and radio observations, and its contribution to the total IR luminosity is estimated from the broadband SED fittings using MAGPHYS.
Results: With the new NOEMA interferometric imaging, we confirm that the source is a unique dusty galaxy. It has no obvious counterpart in the optical and even NIR images observed with HST at λ ≲ 1.4 μm. Photometric-redshift analyses from both stellar and dust SED suggest it to likely be at z ≳ 4, though a lower redshift at z ≳ 3.1 cannot be fully ruled out (at 90% confidence interval). Explaining its unusual optical-to-NIR properties requires an old stellar population (∼0.67 Gyr), coexisting with a very dusty ongoing starburst component. The latter is contributing to the FIR emission, with its rest-frame UV and optical light being largely obscured along our line of sight. If the observed fluxes at the rest-frame optical/NIR wavelengths were mainly contributed by old stars, a total stellar mass of ∼3.5 × 1011 M⊙ would be obtained. An X-ray spectral analysis suggests that this galaxy harbors a heavily obscured AGN with NH = 3.3+2.0-1.7 × 1023 cm-2 and an intrinsic 2-10 keV luminosity of Lx ∼ 2.6 × 1044 erg s-1, which places this object among distant type 2 quasars. The radio emission of the source is extremely bright, which is an order of magnitude higher than the star-formation-powered emission, making it one of the most distant radio-luminous dusty galaxies.
Conclusions: The combined characteristics of the galaxy suggest that the source appears to have been caught in a rare but critical transition stage in the evolution of submillimeter galaxies, where we are witnessing the birth of a young AGN and possibly the earliest stage of its jet formation and feedback. Title: Predictability of the Solar Cycle Over One Cycle Authors: Jiang, Jie; Wang, Jing-Xiu; Jiao, Qi-Rong; Cao, Jin-Bin Bibcode: 2018ApJ...863..159J Altcode: 2018arXiv180701543J The prediction of the strength of future solar cycles is of interest because of its practical significance for space weather and as a test of our theoretical understanding of the solar cycle. The Babcock-Leighton mechanism allows predictions by assimilating the observed magnetic field on the surface. Since the emergence of sunspot groups has random properties, making it impossible to accurately predict the solar cycle and strongly limiting the scope of cycle predictions, we develop a scheme to investigate the predictability of the solar cycle over one cycle. When a cycle has been ongoing for more than three years, the sunspot group emergence can be predicted along with its uncertainty during the rest time of the cycle. The method for this prediction is to start by generating a set of random realizations that obey the statistical relations of the sunspot emergence. We then use a surface flux transport model to calculate the possible axial dipole moment evolutions. The correlation between the axial dipole moment at cycle minimum and the subsequent cycle strength and other empirical properties of solar cycles are used to predict the possible profiles of the subsequent cycle. We apply this scheme to predict the large-scale field evolution from 2018 to the end of cycle 25, whose maximum strength is expected to lie in the range from 93 to 155 with a probability of 95%. Title: A Long Decay of X-Ray Flux and Spectral Evolution in the Supersoft Active Galactic Nucleus GSN 069 Authors: Shu, X. W.; Wang, S. S.; Dou, L. M.; Jiang, N.; Wang, J. X.; Wang, T. G. Bibcode: 2018ApJ...857L..16S Altcode: 2018arXiv180900319S GSN 069 is an optically identified very low-mass active galactic nuclei (AGN) that shows supersoft X-ray emission. The source is known to exhibit a huge X-ray outburst, with flux increased by more than a factor of ∼240 compared to the quiescence state. We report its long-term evolution in the X-ray flux and spectral variations over a timescale of ∼decade, using both new and archival X-ray observations from the XMM-Newton and Swift. The new Swift observations detected the source in its lowest level of X-ray activity since the outburst, a factor of ∼4 lower in the 0.2-2 keV flux than that obtained with the XMM-Newton observations nearly eight years ago. Combining with the historical X-ray measurements, we find that the X-ray flux is decreasing slowly. There seemed to be spectral softening associated with the drop of X-ray flux. In addition, we find evidence for the presence of a weak, variable, hard X-ray component, in addition to the dominant thermal blackbody emission reported before. The long decay of X-ray flux and spectral evolution, as well as the supersoft X-ray spectra, suggest that the source could be a tidal disruption event (TDE), though a highly variable AGN cannot be fully ruled out. Further continued X-ray monitoring would be required to test the TDE interpretation, by better determining the flux evolution in the decay phase. Title: Linking black hole growth with host galaxies: the accretion-stellar mass relation and its cosmic evolution Authors: Yang, G.; Brandt, W. N.; Vito, F.; Chen, C. -T. J.; Trump, J. R.; Luo, B.; Sun, M. Y.; Xue, Y. Q.; Koekemoer, A. M.; Schneider, D. P.; Vignali, C.; Wang, J. -X. Bibcode: 2018MNRAS.475.1887Y Altcode: 2017arXiv171009399Y Previous studies suggest that the growth of supermassive black holes (SMBHs) may be fundamentally related to host-galaxy stellar mass (M⋆). To investigate this SMBH growth-M⋆ relation in detail, we calculate long-term SMBH accretion rate as a function of M⋆ and redshift [\overlineBHAR(M_{\star }, z)] over ranges of log (M⋆/M⊙) = 9.5-12 and z = 0.4-4. Our \overlineBHAR(M_{\star }, z) is constrained by high-quality survey data (GOODS-South, GOODS-North and COSMOS), and by the stellar mass function and the X-ray luminosity function. At a given M⋆, \overlineBHAR is higher at high redshift. This redshift dependence is stronger in more massive systems [for log (M⋆/M⊙) ≈ 11.5, \overlineBHAR is three decades higher at z = 4 than at z = 0.5], possibly due to AGN feedback. Our results indicate that the ratio between \overlineBHAR and average star formation rate (\overlineSFR) rises towards high M⋆ at a given redshift. This \overlineBHAR/\overlineSFR dependence on M⋆ does not support the scenario that SMBH and galaxy growth are in lockstep. We calculate SMBH mass history [MBH(z)] based on our \overlineBHAR(M_{\star }, z) and the M⋆(z) from the literature, and find that the MBH-M⋆ relation has weak redshift evolution since z ≈ 2. The MBH/M⋆ ratio is higher towards massive galaxies: it rises from ≈1/5000 at log M⋆ ≲ 10.5 to ≈1/500 at log M⋆ ≳ 11.2. Our predicted MBH/M⋆ ratio at high M⋆ is similar to that observed in local giant ellipticals, suggesting that SMBH growth from mergers is unlikely to dominate over growth from accretion. Title: Automatic Solar Seeing Observations at Mt. Wumingshan in Western China Authors: Song, T. F.; Wen, Y. M.; Liu, Y.; Elmhamdi, A.; Kordi, A. S.; Zhao, M. Y.; Zhang, X. F.; Li, X. B.; Wang, J. X.; Fu, Y.; Cheng, X. M.; Xu, F. Y. Bibcode: 2018SoPh..293...37S Altcode: Mountain Wumingshan (Mt. WMS) is located in the southeastern foot of the Tibet Plateau with an altitude of 4,800 m. It is one of the candidate sites to place China's next-generation large-scale solar telescope. A temporary observation platform has been built at Mt. WMS, but there is still a great need of a stable solar-seeing monitoring for long-term observations. Based on the preliminary studies on the Solar Differential Image Motion Monitor (SDIMM) of the Yunnan Observatories, we built an improved version of this early prototype, which is called Wumingshan Mountain Automated Solar Differential Image Motion Monitor (WMA-SDIMM). We develop the automatic system of the WMA-SDIMM, investigate the reliability and precision of our measurements by error analysis and comparison testing, and present the statistical results from October 2016 to September 2017 at Mt. WMS. WMA-SDIMM works very well at Mt. WMS and is quite suitable for long-period daytime seeing observations. Title: A prediction of the solar cycle 25 Authors: Jiang, Jie; Wang, Jing-Xiu; Jiao, Qi-Rong Bibcode: 2018IAUS..340..327J Altcode: Here we report our recent prediction of the solar cycle 25 based on a newly developed scheme, which is used to investigate the predictability of the solar cycle over one cycle. The scheme is a combination of the empirical properties of solar cycles and a surface flux transport model to get the possible axial dipole moment evolution at a few years before cycle minimum, by which to get the subsequent cycle strength based on the correlation between the axial dipole moment at cycle minimum and the subsequent cycle strength. We apply this scheme to predict the large-scale field evolution since 2018 onwards. The results show that the northern polar field will keep on increasing, while the southern polar field almost keeps flat by the end of cycle 24. This leads to the cycle 25 strength of 125 +/- 32, which is about 10% stronger than cycle 24 according to the mean value. Title: A Study of External Magnetic Reconnection that Triggers a Solar Eruption Authors: Zhou, G. P.; Zhang, J.; Wang, J. X.; Wheatland, M. S. Bibcode: 2017ApJ...851L...1Z Altcode: External magnetic reconnection (EMR) is suggested to play an essential role in triggering a solar eruption, but is rarely directly observed. Here, we report on a filament eruption on 2014 October 3 that apparently involves the process of an early EMR. A total of 1.7 × 1020 Mx flux was first canceled along the filament-related polarity inversion line over 12 hr, and then the filament axis started to brighten in extreme ultraviolet (EUV). An impulsive EUV brightening began 30 minutes later, and we attribute this to EMR, as it is located at the center of a bidirectional outflow with a velocity of 60-75 km s-1 along large-scale magnetic loops from active regions NOAA 12178 and 12179, respectively, and over the filament mentioned above. Following the EMR, the filament was activated; then, partial eruption occurred 6 minutes later in the west, in which the decay index above the magnetic flux rope (MFR) reached the critical value of 1.5. The observations are interpreted in terms of underlying magnetic flux cancelation leading to the buildup and eventual formation of the MFR with a filament embedded in it, and the MFR is elevated later. The activated MFR rises and pushes the overlying sheared field and forms a current sheet causing the EMR. The EMR in turn weakens the constraining effect of the overlying field, leading to the arising of the MFR, and subsequently erupting due to torus instability. Title: Deepest View of AGN X-Ray Variability with the 7 Ms Chandra Deep Field-South Survey Authors: Zheng, X. C.; Xue, Y. Q.; Brandt, W. N.; Li, J. Y.; Paolillo, M.; Yang, G.; Zhu, S. F.; Luo, B.; Sun, M. Y.; Hughes, T. M.; Bauer, F. E.; Vito, F.; Wang, J. X.; Liu, T.; Vignali, C.; Shu, X. W. Bibcode: 2017ApJ...849..127Z Altcode: 2017arXiv171004358Z We systematically analyze the X-ray variability of active galactic nuclei (AGNs) in the 7 Ms Chandra Deep Field-South survey. On the longest timescale (≈17 years), we find only a weak (if any) dependence of X-ray variability amplitudes on energy bands or obscuration. We use four different power spectral density (PSD) models to fit the anticorrelation between normalized excess variance ({σ }{nxv}2) and luminosity, and obtain a best-fit power-law index β ={1.16}-0.05+0.05 for the low-frequency part of the AGN PSD. We also divide the whole light curves into four epochs in order to inspect the dependence of {σ }{nxv}2 on these timescales, finding an overall increasing trend. The analysis of these shorter light curves also infers a β of ∼1.3 that is consistent with the above-derived β, which is larger than the frequently assumed value of β =1. We then investigate the evolution of {σ }{nxv}2. No definitive conclusion is reached because of limited source statistics, but if present, the observed trend goes in the direction of decreasing AGN variability at fixed luminosity toward high redshifts. We also search for transient events and find six notable candidate events with our considered criteria. Two of them may be a new type of fast transient events, one of which is reported here for the first time. We therefore estimate a rate of fast outbursts < \dot{N}> ={1.0}-0.7+1.1× {10}-3 {{galaxy}}-1 {{yr}}-1 and a tidal disruption event (TDE) rate < {\dot{N}}{TDE}> ={8.6}-4.9+8.5× {10}-5 {{galaxy}}-1 {{yr}}-1 assuming the other four long outbursts to be TDEs. Title: Tracing the accretion history of supermassive black holes through X-ray variability: results from the ChandraDeep Field-South Authors: Paolillo, M.; Papadakis, I.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Tozzi, P.; Shemmer, O.; Allevato, V.; Bauer, F. E.; Comastri, A.; Gilli, R.; Koekemoer, A. M.; Liu, T.; Vignali, C.; Vito, F.; Yang, G.; Wang, J. X.; Zheng, X. C. Bibcode: 2017MNRAS.471.4398P Altcode: 2017arXiv170705332P We study the X-ray variability properties of distant active galactic nuclei (AGNs) in the ChandraDeep Field-South region over 17 yr, up to z ∼ 4, and compare them with those predicted by models based on local samples. We use the results of Monte Carlo simulations to account for the biases introduced by the discontinuous sampling and the low-count regime. We confirm that variability is a ubiquitous property of AGNs, with no clear dependence on the density of the environment. The variability properties of high-z AGNs, over different temporal time-scales, are most consistent with a power spectral density (PSD) described by a broken (or bending) power law, similar to nearby AGNs. We confirm the presence of an anticorrelation between luminosity and variability, resulting from the dependence of variability on black hole (BH) mass and accretion rate. We explore different models, finding that our acceptable solutions predict that BH mass influences the value of the PSD break frequency, while the Eddington ratio λEdd affects the PSD break frequency and, possibly, the PSD amplitude as well. We derive the evolution of the average λEdd as a function of redshift, finding results in agreement with measurements based on different estimators. The large statistical uncertainties make our results consistent with a constant Eddington ratio, although one of our models suggest a possible increase of λEdd with lookback time up to z ∼ 2-3. We conclude that variability is a viable mean to trace the accretion history of supermassive BHs, whose usefulness will increase with future, wide-field/large effective area X-ray missions. Title: VizieR Online Data Catalog: 16yrs of AGNs X-ray spectral analyses from 7Ms CDF-S (Liu+, 2017) Authors: Liu, T.; Tozzi, P.; Wang, J. -X.; Brandt, W. N.; Vignali, C.; Xue, Y.; Schneider, D. P.; Comastri, A.; Yang, G.; Bauer, F. E.; Paolillo, M.; Luo, B.; Gilli, R.; Wang, Q. D.; Giavalisco, M.; Ji, Z.; Alexander, D. M.; Mainieri, V.; Shemmer, O.; Koekemoer, A.; Risaliti, G. Bibcode: 2017yCat..22320008L Altcode: The 7Ms CDF-S survey is comprised of observations performed between 1999 October 14, and 2016 March 24, (UTC). Excluding one observation compromised by telemetry saturation and other issues (ObsID 581), there are 102 observations (observation IDs listed in Table 1) in the data set. The exposures collected across 16 years can be grouped into four distinct periods, each spanning 2-21 months.

Table 1: --------------------------------------------------------------------------- Period Observation Date Time Span Exposure Time --------------------------------------------------------------------------- I 1999.10-2000.12 14 months 1Ms 11 ObsIDs: 1431-0 1431-1 441 582 2406 2405 2312 1672 2409 2313 2239

II 2007.09-2007.11 2 months 1Ms 12 ObsIDs: 8591 9593 9718 8593 8597 8595 8592 8596 9575 9578 8594 9596

III 2010.03-2010.07 4 months 2Ms 31 ObsIDs: 12043 12123 12044 12128 12045 12129 12135 12046 12047 12137 12138 12055 12213 12048 12049 12050 12222 12219 12051 12218 12223 12052 12220 12053 12054 12230 12231 12227 12233 12232 12234

IV 2014.06-2016.03 21 months 3Ms 48 ObsIDs: 16183 16180 16456 16641 16457 16644 16463 17417 17416 16454 16176 16175 16178 16177 16620 16462 17535 17542 16184 16182 16181 17546 16186 16187 16188 16450 16190 16189 17556 16179 17573 17633 17634 16453 16451 16461 16191 16460 16459 17552 16455 16458 17677 18709 18719 16452 18730 16185 ---------------------------------------------------------------------------

(4 data files). Title: Black Hole Growth Is Mainly Linked to Host-galaxy Stellar Mass Rather Than Star Formation Rate Authors: Yang, G.; Chen, C. -T. J.; Vito, F.; Brandt, W. N.; Alexander, D. M.; Luo, B.; Sun, M. Y.; Xue, Y. Q.; Bauer, F. E.; Koekemoer, A. M.; Lehmer, B. D.; Liu, T.; Schneider, D. P.; Shemmer, O.; Trump, J. R.; Vignali, C.; Wang, J. -X. Bibcode: 2017ApJ...842...72Y Altcode: 2017arXiv170406658Y We investigate the dependence of black hole accretion rate (BHAR) on host-galaxy star formation rate (SFR) and stellar mass (M *) in the CANDELS/GOODS-South field in the redshift range of 0.5≤slant z< 2.0. Our sample consists of ≈ {{18,000}} galaxies, allowing us to probe galaxies with 0.1{M}⊙ {{yr}}-1≲ {SFR}≲ 100 {M}⊙ {{yr}}-1 and/or {10}8{M}⊙ ≲ {M}* ≲ {10}11 {M}⊙ . We use sample-mean BHAR to approximate long-term average BHAR. Our sample-mean BHARs are derived from the Chandra Deep Field-South 7 Ms observations, while the SFRs and M * have been estimated by the CANDELS team through spectral energy distribution fitting. The average BHAR is correlated positively with both SFR and M *, and the BHAR-SFR and BHAR-M * relations can both be described acceptably by linear models with a slope of unity. However, BHAR appears to be correlated more strongly with M * than SFR. This result indicates that M * is the primary host-galaxy property related to supermassive black hole (SMBH) growth, and the apparent BHAR-SFR relation is largely a secondary effect due to the star-forming main sequence. Among our sources, massive galaxies ({M}* ≳ {10}10{M}⊙ ) have significantly higher BHAR/SFR ratios than less massive galaxies, indicating that the former have higher SMBH fueling efficiency and/or higher SMBH occupation fraction than the latter. Our results can naturally explain the observed proportionality between {M}{BH} and M * for local giant ellipticals and suggest that their {M}{BH}/{M}* is higher than that of local star-forming galaxies. Among local star-forming galaxies, massive systems might have higher {M}{BH}/{M}* compared to dwarfs. Title: Central Engine and Host Galaxy of RXJ 1301.9+2747: A Multiwavelength View of a Low-mass Black Hole Active Galactic Nuclei with Ultra-soft X-Ray Emission Authors: Shu, X. W.; Wang, T. G.; Jiang, N.; Wang, J. X.; Sun, L. M.; Zhou, H. Y. Bibcode: 2017ApJ...837....3S Altcode: 2017arXiv170402886S RXJ 1301.9+2747 is an optically identified very-low-mass AGN candidate with {M}{BH}∼ 1× {10}6 {M}⊙ , which shows extremely soft X-ray emission and unusual X-ray variability in the form of short-lived flares. We present an analysis of multiwavelength observations of RXJ 1301.9+2747 in order to study the properties of the active nucleus and its host galaxy. The UV-to-X-ray spectrum in the quiescent state can be well and self-consistently described by a thermal and a Comptonized emission from the accretion disk, with the black body dominating ∼70% of the X-rays in the 0.2-2 keV. The same model can describe the X-ray spectrum in the flare state, but the Comptonized component becomes dominant (∼80%). The best fit implies an Eddington ratio of ∼0.14 and a black-hole mass of (1.7-2.8)× {10}6 M ⊙, in agreement with the estimation from the optical data within errors. However, the best-fitting model under predicts the optical flux for the HST point source by a factor of ∼2. The excess of nuclear optical emission could be attributed to a nuclear stellar cluster, which is frequently seen in low-mass AGNs. The X-ray to optical spectral slope ({α }{ox}) is lower than in most other active galaxies, which may be attributed to intrinsically X-ray weakness due to very little hot and optically thin coronal emission. We performed a pilot search for weak or hidden broad emission lines using optical spectropolarimetry observations, but no polarized broad lines are detected. The host galaxy appears to be a disk galaxy with a boxy pseudobulge or nuclear bar accounting for ∼15% of the total starlight, which is consistent with the general characteristics of the host of low-mass AGNs. Title: VizieR Online Data Catalog: Chandra Deep Field-South survey: 7Ms sources (Luo+, 2017) Authors: Luo, B.; Brandt, W. N.; Xue, Y. Q.; Lehmer, B.; Alexander, D. M.; Bauer, F. E.; Vito, F.; Yang, G.; Basu-Zych, A. R.; Comastri, A.; Gilli, R.; Gu, Q. -S.; Hornschemeier, A. E.; Koekemoer, A.; Liu, T.; Mainieri, V.; Paolillo, M.; Ranalli, P.; Rosati, P.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tozzi, P.; Vignali, C.; Wang, J. -X. Bibcode: 2017yCat..22280002L Altcode: The 7Ms CDF-S contains 102 Chandra ACIS-I observations, with a total cleaned exposure time of 6.727Ms, taken in four separate epochs of time. The basic information on these observations is listed in Table 1.

There were 48 recent observations acquired between 2014 June 9 and 2016 March 24, which constitute the last 3Ms of exposure of the 7Ms CDF-S. The first 1Ms of exposure consists of 11 observations taken between 1999 and 2000 (Giacconi+ 2002, J/ApJS/139/369; Rosati+ 2002ApJ...566..667R; Alexander+ 2003, J/AJ/126/539), the next 1Ms of exposure consists of 12 observations taken in 2007 (Luo+ 2008, J/ApJS/179/19), and another 2Ms of exposure includes 31 observations in 2010 (Xue+ 2011, J/ApJS/195/10).

The total area covered by the 7Ms CDF-S is 484.2arcmin2.

(3 data files). Title: VizieR Online Data Catalog: 6Ms Chandra long-term analyses of AGNs (Yang+, 2016) Authors: Yang, G.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Bauer, F. E.; Sun, M. Y.; Kim, S.; Schulze, S.; Zheng, X. C.; Paolillo, M.; Shemmer, O.; Liu, T.; Schneider, D. P.; Vignali, C.; Vito, F.; Wang, J. -X. Bibcode: 2017yCat..18310145Y Altcode: This work is based on the Chandra CDF-S data. The observations were taken from 1999 October to 2015 January with a total observation time of 5.7Ms. In total, there are 84 observations utilized with median exposure time ~60ks. All of the 84 observations were performed using the Advanced CCD Imaging Spectrometer imaging array (ACIS-I). See B. Luo et al. 2016, in prep (L16) for more observation details. Sixty-eight sources are selected with 649-11283 counts; the median number of counts is 1399.

(1 data file). Title: The Chandra Deep Field-South Survey: 7 Ms Source Catalogs Authors: Luo, B.; Brandt, W. N.; Xue, Y. Q.; Lehmer, B.; Alexander, D. M.; Bauer, F. E.; Vito, F.; Yang, G.; Basu-Zych, A. R.; Comastri, A.; Gilli, R.; Gu, Q. -S.; Hornschemeier, A. E.; Koekemoer, A.; Liu, T.; Mainieri, V.; Paolillo, M.; Ranalli, P.; Rosati, P.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tozzi, P.; Vignali, C.; Wang, J. -X. Bibcode: 2017ApJS..228....2L Altcode: 2016arXiv161103501L We present X-ray source catalogs for the ≈7 Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2 arcmin2. Utilizing WAVDETECT for initial source detection and ACIS Extract for photometric extraction and significance assessment, we create a main source catalog containing 1008 sources that are detected in up to three X-ray bands: 0.5-7.0 keV, 0.5-2.0 keV, and 2-7 keV. A supplementary source catalog is also provided, including 47 lower-significance sources that have bright ({K}s≤slant 23) near-infrared counterparts. We identify multiwavelength counterparts for 992 (98.4%) of the main-catalog sources, and we collect redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, we identify 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous ≈4 Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. We have achieved unprecedented X-ray sensitivity with average flux limits over the central ≈1 arcmin2 region of ≈1.9 × 10-17, 6.4 × 10-18, and 2.7 × 10-17 erg cm-2 s-1 in the three X-ray bands, respectively. We provide cumulative number-count measurements observing, for the first time, that normal galaxies start to dominate the X-ray source population at the faintest 0.5-2.0 keV flux levels. The highest X-ray source density reaches ≈50,500 deg-2, and 47% ± 4% of these sources are AGNs (≈23,900 deg-2). Title: VizieR Online Data Catalog: LAMOST DR2 catalogs (Luo+, 2016) Authors: Luo, A. -L.; Zhao, Y. -H.; Zhao, G.; Deng, L. -C.; Liu, X. -W.; Jing, Y. -P.; Wang, G.; Zhang, H. -T.; Shi, J. -R.; Cui, X. -Q.; Chu, Y. -Q.; Li, G. -P.; Bai, Z. -R.; Wu, Y.; Cai, Y.; Cao, S. -Y.; Cao, Z. -H.; Carlin, J. L.; Chen, H. -Y.; Chen, J. -J.; Chen, K. -X.; Chen, L.; Chen, X. -L.; Chen, X. -Y.; Chen, Y.; Christlieb, N.; Chu, J. -R.; Cui, C. -Z.; Dong, Y. -Q.; Du, B.; Fan, D. -W.; Feng, L.; Fu, J. -N.; Gao, P.; Gong, X. -F.; Gu, B. -Z.; Guo, Y. -X.; Han, Z. -W.; He, B. -L.; Hou, J. -L.; Hou, Y. -H.; Hou, W.; Hu, H. -Z.; Hu, N. -S.; Hu, Z. -W.; Huo, Z. -Y.; Jia, L.; Jiang, F. -H.; Jiang, X.; Jiang, Z. -B.; Jin, G.; Kong, X.; Kong, X.; Lei, Y. -J.; Li, A. -H.; Li, C. -H.; Li, G. -W.; Li, H. -N.; Li, J.; Li, Q.; Li, S.; Li, S. -S.; Li, X. -N.; Li, Y.; Li, Y. -B.; Li, Y. -P.; Liang, Y.; Lin, C. -C.; Liu, C.; Liu, G. -R.; Liu, G. -Q.; Liu, Z. -G.; Lu, W. -Z.; Luo, Y.; Mao, Y. -D.; Newberg, H.; Ni, J. -J.; Qi, Z. -X.; Qi, Y. -J.; Shen, S. -Y.; Shi, H. -M.; Song, J.; Song, Y. -H.; Su, D. -Q.; Su, H. -J.; Tang, Z. -H.; Tao, Q. -S.; Tian, Y.; Wang, D.; Wang, D. -Q.; Wang, F. -F.; Wang, G. -M.; Wang, H.; Wang, H. -C.; Wang, J.; Wang, J. -N.; Wang, J. -L.; Wang, J. -P.; Wang, J. -X.; Wang, L.; Wang, M. -X.; Wang, S. -G.; Wang, S. -Q.; Wang, X.; Wang, Y. -N.; Wang, Y.; Wang, Y. -F.; Wang, Y. -F.; Wei, P.; Wei, M. -Z.; Wu, H.; Wu, K. -F.; Wu, X. -B.; Wu, Y. -Z.; Xing, X. -Z.; Xu, L. -Z.; Xu, X. -Q.; Xu, Y.; Yan, T. -S.; Yang, D. -H.; Yang, H. -F.; Yang, H. -Q.; Yang, M.; Yao, Z. -Q.; Yu, Y.; Yuan, H.; Yuan, H. -B.; Yuan, H. -L.; Yuan, W. -M.; Zhai, C.; Zhang, E. -P.; Zhang, H. -W.; Zhang, J. -N.; Zhang, L. -P.; Zhang, W.; Zhang, Y.; Zhang, Y. -X.; Zhang, Z. -C.; Zhao, M.; Zhou, F.; Zhou, X.; Zhu, J.; Zhu, Y. -T.; Zou, S. -C.; Zuo, F. Bibcode: 2016yCat.5149....0L Altcode: There are a couple of corrections been made in this releasing:

Recalculated all the errors of Teff, Logg, Fe/H and rv in the AFGK catalog. Refer to the DR2 paper (in preparation) for details.

Compare to the previous internal releasing, some extra spectra has been added into this version of releasing: STAR from 3,779,597 to 3,843,597, increased 63,923; GALAXY from 37,665 to 47,036, increased 9,371; QSO from 8,633 to 13,262, increased 4,629.

The major contribution to this increasing is that we applied a new method to reduce the data which previously was abandoned due to lack of standard stars with high enough S/N. Refer to the paper 'LAMOST Spectrograph Response Curves: Stability and Application to flux calibration' (in preparation) for details.

There are also a small amount of increasing is due to the correction of fiber flag, and to the eye check work, etc.

(5 data files). Title: The deepest X-ray view of high-redshift galaxies: constraints on low-rate black hole accretion Authors: Vito, F.; Gilli, R.; Vignali, C.; Brandt, W. N.; Comastri, A.; Yang, G.; Lehmer, B. D.; Luo, B.; Basu-Zych, A.; Bauer, F. E.; Cappelluti, N.; Koekemoer, A.; Mainieri, V.; Paolillo, M.; Ranalli, P.; Shemmer, O.; Trump, J.; Wang, J. X.; Xue, Y. Q. Bibcode: 2016MNRAS.463..348V Altcode: 2016MNRAS.tmp.1093V; 2016arXiv160802614V We exploit the 7 Ms Chandra observations in the Chandra Deep Field-South (CDF-S), the deepest X-ray survey to date, coupled with CANDELS/GOODS-S data, to measure the total X-ray emission arising from 2076 galaxies at 3.5 ≤ z < 6.5. This aim is achieved by stacking the Chandra data at the positions of optically selected galaxies, reaching effective exposure times of ≥109s. We detect significant (>3.7σ) X-ray emission from massive galaxies at z ≈ 4. We also report the detection of massive galaxies at z ≈ 5 at a 99.7 per cent confidence level (2.7σ), the highest significance ever obtained for X-ray emission from galaxies at such high redshifts. No significant signal is detected from galaxies at even higher redshifts. The stacking results place constraints on the BHAD associated with the known high-redshift galaxy samples, as well as on the SFRD at high redshift, assuming a range of prescriptions for X-ray emission due to X- ray binaries. We find that the X-ray emission from our sample is likely dominated by processes related to star formation. Our results show that low-rate mass accretion on to SMBHs in individually X-ray-undetected galaxies is negligible, compared with the BHAD measured for samples of X-ray detected AGN, for cosmic SMBH mass assembly at high redshift. We also place, for the first time, constraints on the faint-end of the AGN X-ray luminosity function (logLX ∼ 42) at z > 4, with evidence for fairly flat slopes. The implications of all of these findings are discussed in the context of the evolution of the AGN population at high redshift. Title: Long-term X-Ray Variability of Typical Active Galactic Nuclei in the Distant Universe Authors: Yang, G.; Brandt, W. N.; Luo, B.; Xue, Y. Q.; Bauer, F. E.; Sun, M. Y.; Kim, S.; Schulze, S.; Zheng, X. C.; Paolillo, M.; Shemmer, O.; Liu, T.; Schneider, D. P.; Vignali, C.; Vito, F.; Wang, J. -X. Bibcode: 2016ApJ...831..145Y Altcode: 2016arXiv160808224Y We perform long-term (≈15 years, observed-frame) X-ray variability analyses of the 68 brightest radio-quiet active galactic nuclei (AGNs) in the 6 Ms Chandra Deep Field-South survey; the majority are in the redshift range of 0.6-3.1, providing access to penetrating rest-frame X-rays up to ≈10-30 keV. Of the 68 sources, 24 are optical spectral type I AGNs, and the rest (44) are type II AGNs. The timescales probed in this work are among the longest for X-ray variability studies of distant AGNs. Photometric analyses reveal widespread photon flux variability: 90% of AGNs are variable above a 95% confidence level, including many X-ray obscured AGNs and several optically classified type II quasars. We characterize the intrinsic X-ray luminosity ({L}{{X}}) and absorption ({N}{{H}}) variability via spectral fitting. Most (74%) sources show {L}{{X}} variability; the variability amplitudes are generally smaller for quasars. A Compton-thick candidate AGN shows variability of its high-energy X-ray flux, indicating the size of reflecting material to be ≲0.3 pc. {L}{{X}} variability is also detected in a broad absorption line quasar. The {N}{{H}} variability amplitude for our sample appears to rise as time separation increases. About 16% of sources show {N}{{H}} variability. One source transitions from an X-ray unobscured to obscured state, while its optical classification remains type I; this behavior indicates the X-ray eclipsing material is not large enough to obscure the whole broad-line region. Title: Probing AGN Accretion History Through X-Ray Variability Authors: Paolillo, Maurizio; Papadakis, I.; Brandt, W. N.; Xue, Y. Q.; Luo, B.; Tozzi, P.; Shemmer, O.; Allevato, V.; Bauer, F.; Koekemoer, A.; Vignali, C.; Vito, F.; Yang, G.; Wang, J. X.; Zheng, X. Bibcode: 2016agnt.confE..39P Altcode: I will present recent results on AGN variability in the CDFS survey. Using over 10 years of X-ray monitoring and comparison with local AGNs we are able to constrain the variability dependence on BH mass and accreton rate, and use it to trace the accretion hisory of the AGN population up to z=3. Title: The Deepest X-Ray View Of High-Redshift Galaxies: Constraints On Low-Rate Black-Hole Accretion Authors: Vito, Fabio; Gilli, R.; Vignali, C.; Brandt, W. N.; Comastri, A.; Yang, G.; Lehmer, B. D.; Luo, B.; Basu-Zych, A.; Bauer, F. E.; Cappelluti, N.; Koekemoer, A.; Mainieri, V.; Paolillo, M.; Ranalli, P.; Shemmer, O.; Trump, J.; Wang, J. X. Bibcode: 2016agnt.confE..41V Altcode: We exploit the new 7 Ms Chandra observations in the CDF-S, the deepest X-ray survey to date, coupled with CANDELS/GOODS- S data, to measure the total X-ray emission arising from 2000 galaxies at 3.5 < z < 6.5. This aim is achieved by stacking the Chandra data at the positions of optically selected galaxies, reaching effective exposure times of >=10^9 s. We detect X-ray emission from z ∼ 4 galaxies at 3 ∼ 5sigma, while no significant signal is detected from galaxies at higher redshifts. The stacking results are used to estimate the black hole accretion rate density (BHAD) and star -formation rate density (SFRD) at high redshift, assuming a range of prescriptions for X-ray emission due to X-ray binaries. We find that X-ray emission from our sample is likely dominated by processes related to star formation. Our results show that low-rate mass accretion onto SMBHs in individually X-ray-undetected galaxies is negligible, compared with the BHAD measured for samples of X-ray detected AGN, for cosmic SMBH mass assembly at high redshift. We also place, for the first time, constraints on the faint-end of the AGN X- ray luminosity function (logLX ∼ 42) at z > 4, with evidence for fairly flat slopes. Title: VizieR Online Data Catalog: Evolution of ~6Ms CDF-S galaxies (Lehmer+, 2016) Authors: Lehmer, B. D.; Basu-Zych, A. R.; Mineo, S.; Brandt, W. N.; Eufrasio, R. T.; Fragos, T.; Hornschemeier, A. E.; Luo, B.; Xue, Y. Q.; Bauer, F. E.; Gilfanov, M.; Ranalli, P.; Schneider, D. P.; Shemmer, O.; Tozzi, P.; Trump, J. R.; Vignali, C.; Wang, J. -X.; Yukita, M.; Zezas, A. Bibcode: 2016yCat..18250007L Altcode: We began with an initial sample of 32508 galaxies in the Great Observatories Origins Deep Survey South (GOODS-S) footprint as presented in Section 2 of Xue et al. (2012, J/ApJ/758/129). We cut our initial sample to the 24941 objects that were within 7' of the mean ~6Ms CDF-S aimpoint, a region where the Chandra point-spread function (PSF) is sharpest and the corresponding X-ray sensitivity is highest. See text for further explanations.

(2 data files). Title: The Evolution of Normal Galaxy X-Ray Emission through Cosmic History: Constraints from the 6 MS Chandra Deep Field-South Authors: Lehmer, B. D.; Basu-Zych, A. R.; Mineo, S.; Brandt, W. N.; Eufrasio, R. T.; Fragos, T.; Hornschemeier, A. E.; Luo, B.; Xue, Y. Q.; Bauer, F. E.; Gilfanov, M.; Ranalli, P.; Schneider, D. P.; Shemmer, O.; Tozzi, P.; Trump, J. R.; Vignali, C.; Wang, J. -X.; Yukita, M.; Zezas, A. Bibcode: 2016ApJ...825....7L Altcode: 2016arXiv160406461L We present measurements of the evolution of normal-galaxy X-ray emission from z\quad ≈ 0-7 using local galaxies and galaxy samples in the ≈6 Ms Chandra Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are observed at rest-frame energies above 2 keV, where the emission is expected to be dominated by X-ray binary (XRB) populations; however, hot gas is expected to provide small contributions to the observed-frame ≲1 keV emission at z ≲ 1. We show that a single scaling relation between X-ray luminosity ({L}{{X}}) and star-formation rate (SFR) literature, is insufficient for characterizing the average X-ray emission at all redshifts. We establish that scaling relations involving not only SFR, but also stellar mass ({M}\star ) and redshift, provide significantly improved characterizations of the average X-ray emission from normal galaxy populations at z\quad ≈ 0-7. We further provide the first empirical constraints on the redshift evolution of X-ray emission from both low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings with {M}\star and SFR, respectively. We find {L}2-10{keV}(LMXB)/{M}\star \propto {(1+z)}2-3 and {L}2-10{keV}(HMXB)/SFR \propto \quad (1+z), and show that these relations are consistent with XRB population-synthesis model predictions, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. We discuss how emission from XRBs could provide an important source of heating to the intergalactic medium in the early universe, exceeding that of active galactic nuclei. Title: Observations of Magnetic Flux-rope Oscillation during the Precursor Phase of a Solar Eruption Authors: Zhou, G. P.; Zhang, J.; Wang, J. X. Bibcode: 2016ApJ...823L..19Z Altcode: Based on combined observations from the Interface Region Imaging Spectrograph (IRIS) spectrometer with the coronal emission line of Fe xxi at 1354.08 Å and SDO/AIA images in multiple passbands, we report the finding of the precursor activity manifested as the transverse oscillation of a sigmoid, which is likely a pre-existing magnetic flux rope (MFR), that led to the onset of an X class flare and a fast halo coronal mass ejection (CME) on 2014 September 10. The IRIS slit is situated at a fixed position that is almost vertical to the main axis of the sigmoid structure that has a length of about 1.8 × 105 km. This precursor oscillation lasts for about 13 minutes in the MFR and has velocities in the range of [-9, 11] km s-1 and a period of ∼280 s. Our analysis, which is based on the temperature, density, length, and magnetic field strength of the observed sigmoid, indicates that the nature of the oscillation is a standing wave of fast magnetoacoustic kink mode. We further find that the precursor oscillation is excited by the energy released through an external magnetic reconnection between the unstable MFR and the ambient magnetic field. It is proposed that this precursor activity leads to the dynamic formation of a current sheet underneath the MFR that subsequently reconnects to trigger the onset of the main phase of the flare and the CME. Title: Identification of z ≳ 2 Herschel 500 μM Sources Using Color Deconfusion Authors: Shu, X. W.; Elbaz, D.; Bourne, N.; Schreiber, C.; Wang, T.; Dunlop, J. S.; Fontana, A.; Leiton, R.; Pannella, M.; Okumura, K.; Michałowski, M. J.; Santini, P.; Merlin, E.; Buitrago, F.; Bruce, V. A.; Amorin, R.; Castellano, M.; Derriere, S.; Comastri, A.; Cappelluti, N.; Wang, J. X.; Ferguson, H. C. Bibcode: 2016ApJS..222....4S Altcode: 2015arXiv151200167S We present a new method to search for candidate z ≳ 2 Herschel 500 μm sources in the Great Observatories Origins Deep Survey-North field using a S500 μm/S24 μm “color deconfusion” technique. Potential high-z sources are selected against low-redshift ones from their large 500 to 24 μm flux density ratios. By effectively reducing the contribution from low-redshift populations to the observed 500 μm emission, we are able to identify counterparts to high-z 500 μm sources whose 24 μm fluxes are relatively faint. The recovery of known z ≳ 4 starbursts confirms the efficiency of this approach in selecting high-z Herschel sources. The resulting sample consists of 34 dusty star-forming galaxies at z ≳ 2. The inferred infrared luminosities are in the range 1.5 × 1012-1.8 × 1013 L⊙, corresponding to dust-obscured star formation rates (SFRs) of ∼260-3100 M⊙ yr-1 for a Salpeter initial mass function. Comparison with previous SCUBA 850 μ {{m}}-selected galaxy samples shows that our method is more efficient at selecting high-z dusty galaxies, with a median redshift of z=3.07+/- 0.83 and with 10 of the sources at z ≳ 4. We find that at a fixed luminosity, the dust temperature is ∼5 K cooler than that expected from the {T}d-{L}{{IR}} relation at z\quad ≲ 1, though different temperature selection effects should be taken into account. The radio-detected subsample (excluding three strong active galactic nucleus) follows the far-infrared (far-IR)/radio correlation at lower redshifts, and no evolution with redshift is observed out to z∼ 5, suggesting that the far-IR emission is star formation dominated. The contribution of the high-z Herschel 500 μm sources to the cosmic SFR density is comparable to that of (sub)millimeter galaxy populations at z∼ 2.5 and at least 40% of the extinction-corrected UV samples at z∼ 4. Further investigation into the nature of these high-z dusty galaxies will be crucial for our understanding of the star formation histories and the buildup of stellar mass at the earliest cosmic epochs. Title: Photometric Redshifts in the Hawaii-Hubble Deep Field-North Authors: Yang, G.; Xue, Y. Q.; Luo, B.; Brandt, W. N.; Alexander, D. M.; Bauer, F. E.; Cui, W.; Kong, X.; Lehmer, B. D.; Wang, J. -X.; Wu, X. -B.; Yuan, F.; Yuan, Y. -F.; Zhou, H. Y. Bibcode: 2016IAUS..319...56Y Altcode: We derive z phot for sources in the entire (~0.4 deg2) H-HDF-N field with the EAzY code, based on PSF-matched broad-band (U band to IRAC 4.5 μm) photometry. Our catalog consists of a total of 131,678 sources. We find σNMAD = 0.029 for non-X-ray sources. We also classify each object as a star or galaxy through SED fitting. Furthermore, we match our catalog with the 2 Ms CDF-N main X-ray catalog. For the 462 matched non-stellar X-ray sources, we improve their z phot quality (σNMAD = 0.035) by adding three additional AGN templates. We make our photometry and z phot catalog publicly available. Title: VizieR Online Data Catalog: LAMOST DR1 catalogs (Luo+, 2015) Authors: Luo, A. -L.; Zhao, Y. -H.; Zhao, G.; Deng, L. -C.; Liu, X. -W.; Jing, Y. -P.; Wang, G.; Zhang, H. -T.; Shi, J. -R.; Cui, X. -Q.; Chu, Y. -Q.; Li, G. -P.; Bai, Z. -R.; Wu, Y.; Cai, Y.; Cao, S. -Y.; Cao, Z. -H.; Carlin, J. L.; Chen, H. -Y.; Chen, J. -J.; Chen, K. -X.; Chen, L.; Chen, X. -L.; Chen, X. -Y.; Chen, Y.; Christlieb, N.; Chu, J. -R.; Cui, C. -Z.; Dong, Y. -Q.; Du, B.; Fan, D. -W.; Feng, L.; Fu, J. -N.; Gao, P.; Gong, X. -F.; Gu, B. -Z.; Guo, Y. -X.; Han, Z. -W.; He, B. -L.; Hou, J. -L.; Hou, Y. -H.; Hou, W.; Hu, H. -Z.; Hu, N. -S.; Hu, Z. -W.; Huo, Z. -Y.; Jia, L.; Jiang, F. -H.; Jiang, X.; Jiang, Z. -B.; Jin, G.; Kong, X.; Kong, X.; Lei, Y. -J.; Li, A. -H.; Li, C. -H.; Li, G. -W.; Li, H. -N.; Li, J.; Li, Q.; Li, S.; Li, S. -S.; Li, X. -N.; Li, Y.; Li, Y. -B.; Li, Y. -P.; Liang, Y.; Lin, C. -C.; Liu, C.; Liu, G. -R.; Liu, G. -Q.; Liu, Z. -G.; Lu, W. -Z.; Luo, Y.; Mao, Y. -D.; Newberg, H.; Ni, J. -J.; Qi, Z. -X.; Qi, Y. -J.; Shen, S. -Y.; Shi, H. -M.; Song, J.; Song, Y. -H.; Su, D. -Q.; Su, H. -J.; Tang, Z. -H.; Tao, Q. -S.; Tian, Y.; Wang, D.; Wang, D. -Q.; Wang, F. -F.; Wang, G. -M.; Wang, H.; Wang, H. -C.; Wang, J.; Wan!, G. J. -N.; Wang, J. -L.; Wang, J. -P.; Wang, J. -X.; Wang, L.; Wang, M. -X.; Wang, S. -G.; Wang, S. -Q.; Wang, X.; Wang, Y. -N.; Wang, Y.; Wang, Y. -F.; Wang, Y. -F.; Wei, P.; Wei, M. -Z.; Wu, H.; Wu, K. -F.; Wu, X. -B.; Wu, Y. -Z.; Xing, X. -Z.; Xu, L. -Z.; Xu, X. -Q.; Xu, Y.; Yan, T. -S.; Yang, D. -H.; Yang, H. -F.; Yang, H. -Q.; Yang, M.; Yao, Z. -Q.; Yu, Y.; Yuan, H.; Yuan, H. -B.; Yuan, H. -L.; Yuan, W. -M.; Zhai, C.; Zhang, E. -P.; Zhang, H. -W.; Zhang, J. -N.; Zhang, L. -P.; Zhang, W.; Zhang, Y.; Zhang, Y. -X.; Zhang, Z. -C.; Zhao, M.; Zhou, F.; Zhou, X.; Zhu, J.; Zhu, Y. -T.; Zou, S. -C.; Zuo, F. Bibcode: 2015yCat.5146....0L Altcode: The LAMOST general catalog includes 717469 objects obtained from the LAMOST pilot survey, which contain 648746 stars, 2723 galaxies, 621 quasars and 65406 unknown objects, and 1487200 objects obtained from the LAMOST general survey, which contain 1295583 stars, 9359 galaxies, 4396 quasars and 177862 unknown objects, so this catalog totally includes 2204696 objects including 1,944,329 stars, 12082 galaxies, 5017 quasars and 243268 unknown objects. In this catalog, there are 1186132 objects with SNR of g band larger than 10, 1680794 objects with SNR of i band larger than 10, and 1746202 objects with SNR of g band larger than 10 and SNR of i band larger than 10.

(6 data files). Title: Does the Variation of Solar Intra-network Horizontal Field Follow Sunspot Cycle? Authors: Jin, C. L.; Wang, J. X. Bibcode: 2015ApJ...807...70J Altcode: The ubiquitousness of the solar inter-network horizontal magnetic field has been revealed by space-borne observations with high spatial resolution and polarization sensitivity. However, no consensus has been achieved on the origin of the horizontal field among solar physicists. For a better understanding, in this study, we analyze the cyclic variation of the inter-network horizontal field by using the spectro-polarimeter observations provided by the Solar Optical Telescope on board Hinode, covering the interval from 2008 April to 2015 February. The method of wavelength integration is adopted to achieve a high signal-to-noise ratio. It is found that from 2008 to 2015 the inter-network horizontal field does not vary when solar activity increases, and the average flux density of the inter-network horizontal field is 87 ± 1 G, In addition, the imbalance between horizontal and vertical fields also keeps invariant within the scope of deviation, i.e., 8.7 ± 0.5, from the solar minimum to maximum of solar cycle 24. This result confirms that the inter-network horizontal field is independent of the sunspot cycle. The revelation favors the idea that a local dynamo is creating and maintaining the solar inter-network horizontal field. Title: VizieR Online Data Catalog: SWXCS III. Cluster catalog from 2005-2012 Swift data (Liu+, 2015) Authors: Liu, T.; Tozzi, P.; Tundo, E.; Moretti, A.; Rosati, P.; Wang, J. -X.; Tagliaferri, G.; Campana, S.; Giavalisco, M. Bibcode: 2015yCat..22160028L Altcode: From the entire Swift XRT archive in the period 2005 February-2012 November, we select all the fields that can be used to build an unbiased, serendipitous X-ray cluster catalog.

(2 data files). Title: VizieR Online Data Catalog: Photometric redshifts in the Hawaii-HDF-N (Yang+, 2014) Authors: Yang, G.; Xue, Y. Q.; Luo, B.; Brandt, W. N.; Alexander, D. M.; Bauer, F. E.; Cui, W.; Kong, X.; Lehmer, B. D.; Wang, J. -X.; Wu, X. -B.; Yuan, F.; Yuan, Y. -F.; Zhou, H. Y. Bibcode: 2015yCat..22150027Y Altcode: We collect the U-, B-, V-, R-, I-, z'-, and HK'-band images from Capak+, 2004, J/AJ/127/180, the J- and H-band images from Keenan et al. (2010ApJS..186...94K), and the Ks-band image from Wang et al. (2010, J/ApJS/187/251), respectively. We also make use of an independently observed z'-band image from Ouchi et al. (2009ApJ...706.1136O). The IRAC 3.6, 4.5, 5.8, and 8.0um images were obtained from the Spitzer Heritage Archive, while another set of IRAC 3.6 and 4.5um images were taken from the Spitzer Extended Deep Survey (SEDS) presented in Ashby et al. (2013, J/ApJ/769/80).

(1 data file). Title: Photometric Redshifts in the Hawaii-Hubble Deep Field-North (H-HDF-N) Authors: Yang, G.; Xue, Y. Q.; Luo, B.; Brandt, W. N.; Alexander, D. M.; Bauer, F. E.; Cui, W.; Kong, X.; Lehmer, B. D.; Wang, J. -X.; Wu, X. -B.; Yuan, F.; Yuan, Y. -F.; Zhou, H. Y. Bibcode: 2014ApJS..215...27Y Altcode: 2014arXiv1410.6860Y We derive photometric redshifts (z phot) for sources in the entire (~0.4 deg2) Hawaii-Hubble Deep Field-North (H-HDF-N) field with the EAzY code, based on point-spread-function-matched photometry of 15 broad bands from the ultraviolet (U band) to mid-infrared (IRAC 4.5 μm). Our catalog consists of a total of 131,678 sources. We evaluate the z phot quality by comparing z phot with spectroscopic redshifts (z spec) when available, and find a value of normalized median absolute deviation σNMAD = 0.029 and an outlier fraction of 5.5% (outliers are defined as sources having |zphot - zspec |/(1 + zspec ) > 0.15) for non-X-ray sources. More specifically, we obtain σNMAD = 0.024 with 2.7% outliers for sources brighter than R = 23 mag, σNMAD = 0.035 with 7.4% outliers for sources fainter than R = 23 mag, σNMAD = 0.026 with 3.9% outliers for sources having z < 1, and σNMAD = 0.034 with 9.0% outliers for sources having z > 1. Our z phot quality shows an overall improvement over an earlier z phot work that focused only on the central H-HDF-N area. We also classify each object as a star or galaxy through template spectral energy distribution fitting and complementary morphological parameterization, resulting in 4959 stars and 126,719 galaxies. Furthermore, we match our catalog with the 2 Ms Chandra Deep Field-North main X-ray catalog. For the 462 matched non-stellar X-ray sources (281 having z spec), we improve their z phot quality by adding three additional active galactic nucleus templates, achieving σNMAD = 0.035 and an outlier fraction of 12.5%. We make our catalog publicly available presenting both photometry and z phot, and provide guidance on how to make use of our catalog. Title: The Swift X-ray Cluster Survey Authors: Moretti, A.; Wang, J. X.; Liu, T.; Tundo, E.; Giavalisco, M.; Liu, T.; Tozzi, P.; Campana, S.; Tagliaferri, G. Bibcode: 2014styd.confE..43M Altcode: 2014PoS...233E..43M No abstract at ADS Title: Variation of the solar magnetic flux spectrum during solar cycle 23 Authors: Jin, C. L.; Wang, J. X. Bibcode: 2014JGRA..119...11J Altcode: 2013arXiv1312.5816J By using the unique database of Solar and Heliospheric Observatory/Michelson Doppler Imager full disk magnetograms from September 1996 to January 2011, covering the entire solar cycle 23, we analyze the time-variability of the solar magnetic flux spectrum and study the properties of extended minimum of cycle 23. We totally identify 11.5 million magnetic structures. It has been revealed that magnetic features with different magnetic fluxes exhibit different cycle behaviors. The magnetic features with flux larger than 4.0×1019 Mx, which cover solar active regions and strong network features, show exactly the same variation as sunspots; however, the remaining 82% magnetic features which cover the majority of network elements show anti-phase variation with sunspots. We select a criterion that the monthly sunspot number is less than 20 to represent the Sun's low activity status. Then we find the extended minimum of cycle 23 is characterized by the long duration of low activity status, but the magnitude of magnetic flux in this period is not lower than previous cycle. Both the duration of low activity status and the minimum activity level defined by minimum sunspot number show a century period approximately. The extended minimum of cycle 23 shows similarities with solar cycle 11, which preceded the mini-maxima in later solar cycles. This similarity is suggestive that the solar cycles following cycle 23 are likely to have low activity. Title: Formation and disappearance of a filament Authors: Zhou, G. P.; Wang, J. X.; Tsuneta, S. Bibcode: 2013IAUS..294..593Z Altcode: A continuous observations near an small active region (AR) NOAA 10976 by the Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) on board the Hinode satellite during Dec. 02 2007 from 15:50 UT to 19:59 UT. We observed that: (a) the filament formed by merging parallel fibrils into a twist structure. (b) the filament faded by reconnecting among its own loop structures, or being stripped into pieces.These process are always preceded by the brightening. (c) for the disappearance of the filament, it has close correlation with the activity, like untwisting or expanding, of its corresponding X-ray bright rope. Title: The Swift X-Ray Cluster Survey Authors: Liu, T.; Tozzi, P.; Moretti, A.; Tundo, E.; Rosati, P.; Borgani, S.; Tagliaferri, G.; Capana, S.; Fugazza, D.; D'Avanzo, P.; Wang, J. -X.; Guglielmetti, F. Bibcode: 2013tcec.confE..28L Altcode: No abstract at ADS Title: EXSdetect: an end-to-end software for extended source detection in X-ray images: application to Swift-XRT data Authors: Liu, T.; Tozzi, P.; Tundo, E.; Moretti, A.; Wang, J. -X.; Rosati, P.; Guglielmetti, F. Bibcode: 2013A&A...549A.143L Altcode: 2012arXiv1212.4038L
Aims: We present a stand-alone software (named EXSdetect) for the detection of extended sources in X-ray images. Our goal is to provide a flexible tool capable of detecting extended sources down to the lowest flux levels attainable within instrumental limitations, while maintaining robust photometry, high completeness, and low contamination, regardless of source morphology. EXSdetect was developed mainly to exploit the ever-increasing wealth of archival X-ray data, but is also ideally suited to explore the scientific capabilities of future X-ray facilities, with a strong focus on investigations of distant groups and clusters of galaxies.
Methods: EXSdetect combines a fast Voronoi tessellation code with a friends-of-friends algorithm and an automated deblending procedure. The values of key parameters are matched to fundamental telescope properties such as angular resolution and instrumental background. In addition, the software is designed to permit extensive tests of its performance via simulations of a wide range of observational scenarios.
Results: We applied EXSdetect to simulated data fields modeled to realistically represent the Swift X-ray Cluster Survey (SXCS), which is based on archival data obtained by the X-ray telescope onboard the Swift satellite. We achieve more than 90% completeness for extended sources comprising at least 80 photons in the 0.5-2 keV band, a limit that corresponds to 10-14 erg cm-2 s-1 for the deepest SXCS fields. This detection limit is comparable to the one attained by the most sensitive cluster surveys conducted with much larger X-ray telescopes. While evaluating the performance of EXSdetect, we also explored the impact of improved angular resolution and discuss the ideal properties of the next generation of X-ray survey missions.

The Phyton code EXSdetect is available on the SXCS website http://adlibitum.oats.inaf.it/sxcs Title: Solar Intranetwork Magnetic Elements: Intrinsically Weak or Strong? Authors: Jin, C. L.; Wang, J. X.; Xie, Z. X. Bibcode: 2012SoPh..280...51J Altcode: 2012SoPh..tmp..151J The high spatial resolution observation of a quiet region taken with the Solar Optical Telescope/Spectro-Polarimeter aboard the Hinode spacecraft is analyzed. Based on the Milne-Eddington atmospheric model, the vector magnetic field of the quiet region is derived by fitting the full Stokes profiles of the Fe I 630 nm line pair. We extract intranetwork (IN) region from the quiet region and identify 5058 IN magnetic elements, and study their magnetic properties. As a comparison, the magnetic properties of network (NT) region are also analyzed. The main results are as follows. i) The IN area displays a predominance of weak (hecto-gauss) field concentration, i.e., 99.8 % of IN area shows the weak field. Moreover, the vector magnetic field exhibits concentration toward horizontal direction. However, for the NT region, we discover the coexistence of weak field and strong (kilo-gauss, kG) field. In the IN and NT regions, the filling factor shows almost the same probability distribution function with the peak at about 0.28. ii) All IN magnetic elements show field strength less than 1 kG. However, some NT elements display the coexistence of weak field and strong field. Regardless of NT or IN elements, about 20 % of elements lies in the Doppler blue-shift region. Our results imply that not all magnetic elements lie in the down-draft sites. Title: Quantifying solar superactive regions with vector magnetic field observations Authors: Chen, A. Q.; Wang, J. X. Bibcode: 2012A&A...543A..49C Altcode: 2012arXiv1205.6533C Context. The vector magnetic field characteristics of superactive regions (SARs) hold the key for understanding why SARs are extremely active and provide the guidance in space weather prediction.
Aims: We aim to quantify the characteristics of SARs using the vector magnetograms taken by the Solar Magnetic Field Telescope at Huairou Solar Observatory Station.
Methods: The vector magnetic field characteristics of 14 SARs in solar cycles 22 and 23 were analyzed using the following four parameters: 1) the magnetic flux imbalance between opposite polarities; 2) the total photospheric free magnetic energy; 3) the length of the magnetic neutral line with its steep horizontal magnetic gradient; and 4) the area with strong magnetic shear. Furthermore, we selected another eight large and inactive active regions (ARs), which are called fallow ARs (FARs), to compare them with the SARs.
Results: We found that most of the SARs have a net magnetic flux higher than 7.0 × 1021 Mx, a total photospheric free magnetic energy higher than 1.0 × 1024 erg cm-1, a magnetic neutral line with a steep horizontal magnetic gradient (≥300 G Mm-1) longer than 30 Mm, and an area with strong magnetic shear (shear angle ≥ 80°) greater than 100 Mm2. In contrast, the values of these parameters for the FARs are mostly very low. The Pearson χ2 test was used to examine the significance of the difference between the SARs and FARs, and the results indicate that these two types of ARs can be fairly distinguished by each of these parameters. The significance levels are 99.55%, 99.98%, 99.98%, and 99.96%, respectively. However, no single parameter can distinguish them perfectly. Therefore we propose a composite index based on these parameters, and find that the distinction between the two types of ARs is also significant with a significance level of 99.96%. These results are useful for a better physical understanding of the SAR and FAR. Title: Sun's small-scale magnetic field : from quiet region to polar region Authors: Jin, C. L.; Wang, J. X.; Zhao, M. Bibcode: 2012EAS....55...15J Altcode: In this contribution, we present our recent effort in understanding the solar small-scale magnetic field. Firstly, with the unique data from MDI/SOHO in an interval embodying solar cycle 23, we find three categories of small-scale magnetic elements, and their number variations shows no correlation, anti-correlation and correlation with sunspots, respectively. The possible sources for the three categories of small-scale magnetic elements are discussed. Secondly, by the observations from SOT on board Hinode, we study the properties of vector magnetic field in quiet Sun. The following results are summarized. (1) Two categories of horizontal magnetic elements are disclosed, and most of horizontal elements are associate with the emergence of U-loop. (2) The magnetic field of quiet region is obviously non-potential. The filigrees and network bright points are characterized by strong longitudinal field, large electric helicity and free energy density. (3) For quiet region, the intra-network region displays a predominance of weak field concentration, but network region shows the coexisting of weak field with strong field; For polar region, the strong field occupies 6.7% of the region. (4) On quiet region, the magnetic field mainly resides in the inter-granular lanes. By the observation, we reconstruct an average granular model, for which the detailed distributions of vector fields, Doppler velocity and intensity are obtained. Title: Revision of Solar Spicule Classification Authors: Zhang, Y. Z.; Shibata, K.; Wang, J. X.; Mao, X. J.; Matsumoto, T.; Liu, Y.; Su, J. T. Bibcode: 2012ApJ...750...16Z Altcode: 2012arXiv1202.4518Z Solar spicules are the fundamental magnetic structures in the chromosphere and may play a key role in channeling the chromosphere and corona. Recently, it was suggested by De Pontieu et al. that there were two types of spicules with very different dynamic properties, which were detected by the space-time plot technique in the Ca II H line (3968 Å) wavelength from Hinode/Solar Optical Telescope observations. A "Type I" spicule with a 3-7-minute lifetime undergoes a cycle of upward and downward motions; by contrast, a "Type II" spicule fades away within dozens of seconds without a descending phase. We are motivated by the fact that for a spicule with complicated three-dimensional motion the space-time plot, which is made through a slit on a fixed position, could not match the spicule behavior all the time and might lose its real life story. By revisiting the same data sets, we identify and trace 105 and 102 spicules in the quiet Sun (QS) and coronal hole (CH), respectively, and obtain their statistical dynamic properties. First, we have not found a single convincing example of "Type II" spicules. Second, more than 60% of the identified spicules in each region show a complete cycle, i.e., the majority are "Type I" spicules. Third, the lifetimes of the spicules in the QS and CH are 148 s and 112 s, respectively, but there is no fundamental lifetime difference between the spicules in the QS and CH reported earlier. Therefore, the suggestion of coronal heating by "Type II" spicules should be taken with caution. Title: A Possible Ultra Strong and Broad Fe Kα Emission Line in Seyfert 2 Galaxy IRAS 00521-7054 Authors: Tan, Y.; Wang, J. X.; Shu, X. W.; Zhou, Youyuan Bibcode: 2012ApJ...747L..11T Altcode: 2012arXiv1202.0400T We present XMM-Newton spectra of the Seyfert 2 Galaxy IRAS 00521-7054. A strong feature at ~6 keV (observer's frame) can be formally fitted with a strong (EW = 1.3 ± 0.3 keV in the rest frame) and broad Fe Kα line, extending down to 3 keV. The underlying X-ray continuum could be fitted with an absorbed power law (with Γ = 1.8 ± 0.2 and N H = 5.9+0.6 -0.7 × 1022 cm-2) plus a soft component. If due to relativistically smeared reflection by an X-ray illuminated accretion disk, the spin of the supermassive black hole (SMBH) is constrained to be 0.97+0.03 -0.13 (errors at 90% confidence level for one interesting parameter), and the accretion system is viewed at an inclination angle of 37° ± 4°. This would be the first type 2 active galactic nucleus reported with strong red Fe Kα wing detected which demands a fast rotating SMBH. The unusually large EW would suggest that the light bending effect is strong in this source. Alternatively, the spectra could be fitted by a dual-absorber model (though with a global χ2 higher by ~6 for 283 dof) with N H1 = 7.0 ± 0.8 × 1022 cm-2 covering 100% of the X-ray source, and N H2 = 21.7+5.6 -5.4 × 1022 cm-2 covering 71%, which does not require an extra broad Fe Kα line. Title: On the X-Ray Baldwin Effect in Active Galactic Nuclei Observed by the Chandra High-energy Grating Authors: Shu, X. W.; Wang, J. X.; Yaqoob, T.; Jiang, P.; Zhou, Y. Y. Bibcode: 2012ApJ...744L..21S Altcode: 2011arXiv1112.1569S Using Chandra high-energy grating (HEG) observations of 32 active galactic nuclei (AGNs), we present a systematic study of the X-ray Baldwin effect (XBE; i.e., the anti-correlation between the narrow Fe Kα line equivalent width (EW) and X-ray continuum luminosity for AGN samples) with the highest spectral resolution currently available. We have previously reported an anti-correlation with EWvpropL -0.22 2-10 keV in an HEG sample, and the correlation is much weaker after averaging multiple observations of individual AGNs (EWvpropL -0.13 2-10 keV). This indicates that rapid variation in the X-ray continuum plays an important role in producing the XBE, and such an effect should also be visible in individual AGNs. In this Letter, by normalizing the line EWs and continuum luminosities to the time-averaged values for each AGN in our sample with multiple HEG observations, we find a strong anti-correlation between EW and LX (EW/langEWrangvprop(L/langLrang)-0.82 ± 0.10), consistent with the XBE expected in an individual AGN if the narrow line flux remains constant while the continuum varies. This is first observational evidence that the Fe Kα line flux in a large sample of AGNs lacks a corresponding response to the continuum variation, supporting the fact that the narrow Fe-K line emission originates from a region far from the nucleus. We then performed Monte Carlo simulations to address whether the global XBE can be produced by X-ray continuum variation solely, and found that such an interpretation of the XBE cannot be ruled out statistically. One should thus be very cautious before drawing any scientific conclusion based on an observed XBE. Title: The Latitude Distribution of Small-scale Magnetic Elements in Solar Cycle 23 Authors: Jin, C. L.; Wang, J. X. Bibcode: 2012ApJ...745...39J Altcode: With the unique data set from full-disk observations provided by Michelson Doppler Imager on board the Solar and Heliospheric Observatory in the interval embodying solar cycle 23, we have found that the cyclic variations of numbers and total flux of these small-scale magnetic elements covering fluxes of (2.9-32.0) × 1018 Mx and (4.27-38.01) × 1019 Mx show anticorrelation and correlation with sunspots, respectively. In this study, the time-latitude distributions of these anticorrelated and correlated elements are analyzed. The following results are disclosed: (1) for the correlated elements, the cyclic variations of the total flux in low-latitude and middle-latitude regions show a longer duration of cyclic maximum phase than that of an active region (AR) in the corresponding latitude region; the total flux of these elements shows the accordant south-north asymmetry with that of AR; the time-latitude distribution of their number displays a similar butterfly diagram but with a latitude distribution that is twice as wide as that of sunspots. (2) For the anticorrelated elements, the time-latitude distribution of number shows a solar cycle variation different from the sunspot butterfly diagram; in each latitude, the distribution of anticorrelated elements always shows the anticorrelated variation with that of sunspots; during solar cycle 23, the average speed of the peak latitudinal migration for anticorrelated elements reaches 7.5 deg year-1, almost three times that for sunspots. These results seem to imply that the correlated elements are the debris of decayed sunspots, and the anticorrelated elements have a different source but are affected or modulated by sunspot magnetic field. Title: Statistical properties of superactive regions during solar cycles 19-23 Authors: Chen, A. Q.; Wang, J. X.; Li, J. W.; Feynman, J.; Zhang, J. Bibcode: 2011A&A...534A..47C Altcode: Context. Each solar activity cycle is characterized by a small number of superactive regions (SARs) that produce the most violent of space weather events with the greatest disastrous influence on our living environment.
Aims: We aim to re-parameterize the SARs and study the latitudinal and longitudinal distributions of SARs.
Methods: We select 45 SARs in solar cycles 21-23, according to the following four parameters: 1) the maximum area of sunspot group, 2) the soft X-ray flare index, 3) the 10.7 cm radio peak flux, and 4) the variation in the total solar irradiance. Another 120 SARs given by previous studies of solar cycles 19-23 are also included. The latitudinal and longitudinal distributions of the 165 SARs in both the Carrington frame and the dynamic reference frame during solar cycles 19-23 are studied statistically.
Results: Our results indicate that these 45 SARs produced 44% of all the X class X-ray flares during solar cycles 21-23, and that all the SARs are likely to produce a very fast CME. The latitudinal distributions of SARs display the Maunder butterfly diagrams and SARs occur preferentially in the maximum period of each solar cycle. Northern hemisphere SARs dominated in solar cycles 19 and 20 and southern hemisphere SARs dominated in solar cycles 21 and 22. In solar cycle 23, however, SARs occurred about equally in each hemisphere. There are two active longitudes in both the northern and southern hemispheres, about 160°-200° apart. Applying the improved dynamic reference frame to SARs, we find that SARs rotate faster than the Carrington rate and there is no significant difference between the two hemispheres. The synodic periods are 27.19 days and 27.25 days for the northern and southern hemispheres, respectively. The longitudinal distribution of SARs is significantly non-axisymmetric and about 75% SARs occurred near two active longitudes with half widths of 45°.

Appendix A is available in electronic form at http://www.aanda.org Title: Chandra High-energy Grating Observations of the Fe Kα Line Core in Type II Seyfert Galaxies: A Comparison with Type I Nuclei Authors: Shu, X. W.; Yaqoob, T.; Wang, J. X. Bibcode: 2011ApJ...738..147S Altcode: 2011arXiv1107.0195S We present a study of the core of the Fe Kα emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra high-energy grating. The sample consists of 29 observations of 10 unique sources. We present measurements of the Fe Kα line parameters with the highest spectral resolution currently available. In particular, we derive the most robust intrinsic line widths for some of the sources in the sample to date. We obtained a weighted mean full width at half-maximum (FWHM) of 2000 ± 160 km s-1 for 8 out of 10 sources (the remaining sources had insufficient signal to noise). From a comparison with the optical emission-line widths obtained from spectropolarimetric observations, we found that the location of Fe Kα line-emitting material is a factor of ~0.7-11 times the size of the optical broad-line region. Furthermore, compared to 13 type I active galactic nuclei (AGNs) for which the best Fe Kα line FWHM constraints were obtained, we found no difference in the FWHM distribution or the mean FWHM, and this conclusion is independent of the central black hole mass. This result suggests that the bulk of the Fe Kα line emission may originate from a universal region at the same radius with respect to the gravitational radius, ~3 × 104 rg on average. By examining the correlation between the Fe Kα luminosity and the [O IV] line luminosity, we found a marginal difference in the Fe Kα line flux between type I and type II AGNs, but the spread in the ratio of L Fe to L [O IV] is about two orders of magnitude. Our results confirm the theoretical expectation that the Fe Kα emission-line luminosity cannot trivially be used as a proxy of the intrinsic AGN luminosity, unless a detailed comparison of the data with proper models is applied. Title: The Sun's Small-scale Magnetic Elements in Solar Cycle 23 Authors: Jin, C. L.; Wang, J. X.; Song, Q.; Zhao, H. Bibcode: 2011ApJ...731...37J Altcode: 2011arXiv1102.3728J With the unique database from the Michelson Doppler Imager on board the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic elements is studied. More than 13 million small-scale magnetic elements are selected, and the following results are found. (1) The quiet regions dominated the Sun's magnetic flux for about 8 years in the 12.25 year duration of cycle 23. They contributed (0.94-1.44) ×1023 Mx flux to the Sun from the solar minimum to maximum. The monthly average magnetic flux of the quiet regions is 1.12 times that of the active regions in the cycle. (2) The ratio of quiet region flux to that of the total Sun equally characterizes the course of a solar cycle. The 6 month running average flux ratio of the quiet regions was larger than 90.0% for 28 continuous months from July 2007 to October 2009, which very well characterizes the grand solar minima of cycles 23-24. (3) From the small to the large end of the flux spectrum, the variations of numbers and total flux of the network elements show no correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements, covering the flux of (2.9-32.0)×1018 Mx, occupy 77.2% of the total element number and 37.4% of the quiet-Sun flux. These results provide insight into the reason for anti-correlations of small-scale magnetic activity during the solar cycle. Title: Small-scale magnetic elements in Solar Cycle 23 Authors: Jin, C. L.; Wang, J. X.; Song, Q.; Zhao, H. Bibcode: 2011arXiv1102.3485J Altcode: With the unique database from Michelson Doppler Imager aboard the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic elements is studied. More than 13 million small-scale magnetic elements are selected, and the following results are unclosed. (1) The quiet regions dominated the Sun\textsf{'}s magnetic flux for about 8 years in the 12.25 year duration of Cycle 23. They contributed (0.94 -- 1.44) $\times 10^{23}$ Mx flux to the Sun from the solar minimum to maximum. The monthly average magnetic flux of the quiet regions is 1.12 times that of active regions in the cycle. (2) The ratio of quiet region flux to that of the total Sun equally characterizes the course of a solar cycle. The 6-month running-average flux ratio of quiet region had been larger than 90.0% for 28 continuous months from July 2007 to October 2009, which characterizes very well the grand solar minima of Cycles 23-24. (3) From the small to large end of the flux spectrum, the variations of numbers and total flux of the network elements show no-correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements, covering the flux of (2.9 - 32.0)$\times 10^{18}$ Mx, occupies 77.2% of total element number and 37.4% of quiet Sun flux. These results provide insight into reason for anti-correlated variations of small-scale magnetic activity during the solar cycle. Title: A current sheet traced from the Sun to interplanetary space Authors: Zhou, G. P.; Xiao, C. J.; Wang, J. X.; Wheatland, M. S.; Zhao, H. Bibcode: 2011A&A...525A.156Z Altcode: Context. Magnetic reconnection is a central concept for understanding solar activity, including filament eruptions, flares, and coronal mass ejections (CMEs). The existence of transverse and vertical current sheets, sites where reconnection takes place in the solar atmosphere, is frequently proposed as a precondition for flare/CME models, but is rarely identified in observations.
Aims: We aim at identifying a transverse current sheet that existed in the pre-CME structure and persisted from the CME solar source to interplanetary space.
Methods: STEREO A/B provide us a unique opportunity to calculate the interplanetary current sheets for the magnetic cloud. We analyze such a structure related to the fast halo CME of 2006 December 13 with assembled observations. A current sheet at the front of the magnetic cloud is analyzed to its origin in a transverse current sheet in the CME solar source, which can be revealed in the magnetic field extrapolations, XRT, and LASCO observations.
Results: An interplanetary current sheet is identified as coming from the CME solar source by carefully mapping and examining multiple observations from the Sun to interplanetary space, along with nonlinear force-free magnetic field extrapolations of the active region NOAA 10930.
Conclusions: The structure identified in the pre-flare state is a global transverse current sheet, which plays a role in the CME initiation, and propagates from the corona to interplanetary space. Title: Solar cycle variation of network magnetic elements Authors: Wang, J. X.; Jin, C. L. Bibcode: 2011ASInC...2..163W Altcode: With the unique database from Michelson Doppler Imager aboard the Solar and Heliospheric Observatory in an interval embodying solar cycle 23, the cyclic behavior of solar small-scale magnetic elements is studied. More than 13 million solar network magnetic elements are selected, and the following results are discussed. (1) With increasing flux per element, the number variation of the network elements shows a three-fold scenario: no-correlation, anti-correlation, and correlation with sunspots, respectively. The anti-correlated elements cover flux range of (2.9 - 32.0)× 10^{18} Mx, and occupy 77.2% of total network elements. (2) The latitude distribution of the correlated elements follows the sunspot butterfly diagram in the solar cycle but has wider latitude distribution than sunspots. Furthermore, the anti-correlated elements also show much broad latitude distribution, but a moderate migration toward equator during the solar maximum which was clearly out of phase with sunspots. These results shed new light in understanding anti-correlated variations of small-scale solar activity, e.g., X-ray coronal bright points, and the origin of the Sun's small-scale magnetism. Title: Erratum to: Solar Intranetwork Magnetic Elements: Evolution and Lifetime Authors: Zhou, G. P.; Wang, J. X.; Jin, C. L. Bibcode: 2010SoPh..267..493Z Altcode: 2010SoPh..tmp..221Z; 2010SoPh..tmp..197Z No abstract at ADS Title: Solar Intranetwork Magnetic Elements: Evolution and Lifetime Authors: Zhou, G. P.; Wang, J. X.; Jin, C. L. Bibcode: 2010SoPh..267...63Z Altcode: 2010SoPh..tmp..173Z Based on Hinode SOT/NFI observations with greatly improved spatial and temporal resolution and polarization sensitivity, the lifestory of the intranetwork (IN) magnetic elements are explored in a solar quiet region. A total of 2282 IN elements are followed from their appearance to disappearance and their fluxes measured. By tracing individual IN elements their lifetimes are obtained, which fall in the range from 1 to 20 min. The average lifetime is 2.9±2.0 min. The observed lifetime distribution is well represented by an exponential function. Therefore, the e-fold characteristic lifetime is determined by a least-square fitting to the observations, which is 2.1±0.3 min. The lifetime of IN elements is correlated closely with their flux. The evolution of IN elements is described according to the forms of their birth and disappearance. Based on the lifetime and flux obtained from the new observations, it is estimated that the IN elements have the capacity of heating the corona with a power of 2.1×1028 erg s−1 for the whole Sun. Title: XMM-Newton Observations of the Seyfert 2 Galaxy NGC 7590: The Nature of X-ray Absorption Authors: Shu, X. W.; Liu, T.; Wang, J. X. Bibcode: 2010ApJ...722...96S Altcode: 2010arXiv1008.1502S We present the analysis of three XMM-Newton observations of the Seyfert 2 galaxy NGC 7590. The source was found to have no X-ray absorption in the low spatial resolution ASCA data. The XMM-Newton observations provide a factor of ~10 better spatial resolution than previous ASCA data. We find that the X-ray emission of NGC 7590 is dominated by an off-nuclear ultra-luminous X-ray source and an extended emission from the host galaxy. The nuclear X-ray emission is rather weak compared with the host galaxy. Based on its very low X-ray luminosity as well as the small ratio between the 2-10 keV and the [O III] fluxes, we interpret NGC 7590 as Compton-thick rather than being an "unobscured" Seyfert 2 galaxy. Future higher resolution observations such as Chandra are crucial to shed light on the nature of the NGC 7590 nucleus. Title: X-ray Properties of the z ~ 4.5 Lyα Emitters in the Chandra Deep Field South Region Authors: Zheng, Z. Y.; Wang, J. X.; Finkelstein, S. L.; Malhotra, S.; Rhoads, J. E.; Finkelstein, K. D. Bibcode: 2010ApJ...718...52Z Altcode: 2010arXiv1005.3829Z We report the first X-ray detection of Lyα emitters (LAEs) at redshift z ~ 4.5. One source (J033127.2-274247) is detected in the Extended Chandra Deep Field-South (ECDF-S) X-ray data and has been spectroscopically confirmed as a z = 4.48 quasar with LX = 4.2 × 1044 erg s-1. The single detection gives an Lyα quasar density of ~ 2.7+6.2 -2.2 × 10-6 Mpc-3, consistent with the X-ray luminosity function of quasars. Another 22 LAEs in the central Chandra Deep Field-South region are not detected individually, but their co-added counts yield an S/N = 2.4 (p = 99.83%) detection at soft band, with an effective exposure time of ~36 Ms. Further analysis of the equivalent width (EW) distribution shows that all the signals come from 12 LAE candidates with EWrest< 400 Å and 2 of them contribute about half of the signal. From follow-up spectroscopic observations, we find that one of the two is a low-redshift emission-line galaxy, and the other is a Lyman break galaxy at z = 4.4 with little or no Lyα emission. Excluding these two and combined with ECDF-S data, we derive a 3σ upper limit on the average X-ray flux of F 0.5-2.0 keV < 1.6 × 10-18 erg cm-2 s-1, which corresponds to an average luminosity of langL 0.5-2 keVrang <2.4 × 1042 erg s-1 for z ~ 4.5 LAEs. If the average X-ray emission is due to star formation, it corresponds to a star formation rate (SFR) of <180-530 M sun yr-1. We use this SFR X as an upper limit of the unobscured SFR to constrain the escape fraction of Lyα photons and find a lower limit of f esc,Lyα > 3%-10%. However, our upper limit on the SFR X is ~7 times larger than the upper limit on SFR X on z ~ 3.1 LAEs in the same field and at least 30 times higher than the SFR estimated from Lyα emission. From the average X-ray-to-Lyα line ratio, we estimate that fewer than 3.2% (6.3%) of our LAEs could be high-redshift type 1 (type 2) active galactic nuclei (AGNs) and those hidden AGNs likely show low rest-frame EWs. Title: The Cores of the Fe Kα Lines in Active Galactic Nuclei: An Extended Chandra High Energy Grating Sample Authors: Shu, X. W.; Yaqoob, T.; Wang, J. X. Bibcode: 2010ApJS..187..581S Altcode: 2010arXiv1003.1790S We extend the study of the core of the Fe Kα emission line at ~6.4 keV in Seyfert galaxies reported by Yaqoob & Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z < 0.3. Whilst heavily obscured active galactic nuclei are excluded from the sample, these data offer some of the highest precision measurements of the peak energy of the Fe Kα line, and the highest spectral resolution measurements of the width of the core of the line in unobscured and moderately obscured (N H < 1023 cm-2) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe Kα line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe Kα line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources (~94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 ± 3 eV. The mean FWHM from the subsample of 27 sources was 2060 ± 230 km s-1. The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the Hβ optical emission-line widths (or, for one source, Brα), we find that there is no universal location of the Fe Kα line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe Kα line flux from parsec-scale distances from the putative black hole, down to matter a factor ~2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Fe Kα line EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Fe Kα line. Title: NGC 2992 in an X-ray High State Observed by XMM-Newton: Response of the Relativistic Fe Kα Line to the Continuum Authors: Shu, X. W.; Yaqoob, T.; Murphy, K. D.; Braito, V.; Wang, J. X.; Zheng, W. Bibcode: 2010ApJ...713.1256S Altcode: 2010arXiv1003.1789S We present the analysis of an XMM-Newton observation of the Seyfert galaxy NGC 2992. The source was found in its highest level of X-ray activity yet detected, a factor ~23.5 higher in the 2-10 keV flux than the historical minimum. NGC 2992 is known to exhibit X-ray flaring activity on timescales of days to weeks, and the XMM-Newton data provide at least a factor of ~3 better spectral resolution in the Fe K band than any previously measured flaring X-ray state. We find that there is a broad feature in the ~5-7 keV band that could be interpreted as a relativistic Fe Kα emission line. Its flux appears to have increased in tandem with the 2-10 keV continuum when compared to a previous Suzaku observation when the continuum was a factor of ~8 lower than that during the XMM-Newton observation. The XMM-Newton data are consistent with the general picture that increased X-ray activity and corresponding changes in the Fe Kα line emission occur in the innermost regions of the putative accretion disk. This behavior contrasts with the behavior of other active galactic nuclei in which the Fe Kα line does not respond to variability in the X-ray. Title: Is there more global solar activity on the Sun? Authors: Wang, J. X.; Zhang, Y. Z.; Zhou, G. P.; Wen, Y. Y.; Jiang, J. Bibcode: 2010IAUS..264..251W Altcode: There appear indications of more global activity on the Sun which is larger, much beyond the scale of solar active regions (ARs). These indications include formation, flaring and eruption of the trans-equatorial loops seen in EUV and X-rays, formation and eruption of trans-equatorial filaments, global magnetic connectivity in EUV dimming associated with halo-coronal mass ejections, wide spread of radio burst sources in meter wavelength in the solar corona, and quasi-simultaneous magnetic flux emergence in both hemispheres seen during some major solar events. With examples of a few major events in the last solar cycle we discuss the possibility that there is large or global-scale activity on the Sun. Its spatial scale is many times larger than that of AR and temporal scale is over 10 hours. The exemplified trans-equatorial loops are anchored in ARs and their activity is temporally associated with flares in ARs too. In some sense the flares in ARs appear either as a part of or a precursor of the more global activity. It is likely that the combination of the flares in ARs and the associated global activity is responsible to the major solar-terrestrial events. More efforts in understanding the global activity are undertaken. Title: The Research on the Fast Static Precise Point Position Based on Ridged Estimation Authors: Li, H. J.; Wang, J. X.; Chen, J. P.; Hu, C. W. Bibcode: 2009AcASn..50..438L Altcode: Precise Point Positioning (PPP) has been reported to have a precision at centimeter level in static mode and at centimeter to decimeter level in kinematic mode. However, the application of PPP to real-time is still limited by its long convergence time, typically 30 minutes, which is necessary for the float carrier phase ambiguity resolution. The ambiguity free model of PPP can eliminate the initial phase ambiguities through epoch-difference of phase observations. However, this mode only estimates coordinate differences between two sequential epochs. Therefore, the station coordinates need to be derived with additional methods, e.g., combined with noised range observations. In this paper, based on the phase epoch-difference, a fast static PPP algorithm is developed, where parameters estimation is based on the ridged estimation. The coordinates can be estimated by observations only at two epochs, assuring the fast PPP. Using the 1 hour-data collected on the 295th day of 2007 in Tongji University, a test was carried out. Results show that the coordinate precision can be at centimeter to decimeter level when the initial values are different. Title: Magnetic non-potentiality on the quiet Sun and the filigree Authors: Zhao, Meng; Wang, Jing-Xiu; Jin, Chun-Lan; Zhou, Gui-Ping Bibcode: 2009RAA.....9..933Z Altcode: From the observed vector magnetic fields by the Solar Optical Telescope/Spectro-Polarimeter aboard the satellite Hinode, we have examined whether or not the quiet Sun magnetic fields are non-potential, and how the G-band filigrees and Ca II network bright points (NBPs) are associated with the magnetic non-potentiality. A sizable quiet region in the disk center is selected for this study. The new findings by the study are as follows. (1) The magnetic fields of the quiet region are obviously non-potential. The region-average shear angle is 40o, the average vertical current is 0.016A m-2, and the average free magnetic energy density, 2.7 × 102 erg cm-3. The magnitude of these non-potential quantities is comparable to that in solar active regions. (2) There are overall correlations among current helicity, free magnetic energy and longitudinal fields. The magnetic non-potentiality is mostly concentrated in the close vicinity of network elements which have stronger longitudinal fields. (3) The filigrees and NBPs are magnetically characterized by strong longitudinal fields, large electric helicity, and high free energy density. Because the selected region is away from any enhanced network, these new results can generally be applied to the quiet Sun. The findings imply that stronger network elements play a role in high magnetic non-potentiality in heating the solar atmosphere and in conducting the solar wind. Title: Flare-induced signals in polarization measurements during the X2.6 flare on 2005 January 15 Authors: Zhao, Meng; Wang, Jing-Xiu; Matthews, Sarah; Ming-DeDing; Zhao, Hui; Jin, Chun-Lan Bibcode: 2009RAA.....9..812Z Altcode: Flare-induced signals in polarization measurements which were manifested as apparent polarity reversal in magnetograms have been reported since 1981. We are motivated to further quantify the phenomenon by asking two questions: can we distinguish the flare-induced signals from real magnetic changes during flares, and what we can learn about flare energy release from the flare-induced signals? We select the X2.6 flare that occurred on 2005 January 15, for further study. The flare took place in NOAA active region (AR) 10720 at approximately the central meridian, which makes the interpretation of the vector magnetograms less ambiguous. We have identified that flare-induced signals during this flare appeared in six zones. The zones are located within an average distance of 5 Mm from their weight center to the main magnetic neutral line, have an average size of (0.6±0.4)×1017 cm2, duration of 13±4 min, and flux density change of 181±125 G in the area of reversed polarity. The following new facts have been revealed by this study: (1) the flare-induced signal is also seen in the transverse magnetograms but with smaller magnitude, e.g., about 50 G; (2) the flare-induced signal mainly manifests itself as apparent polarity reversal, but the signal starts and ends as a weakening of flux density; (3) The flare-induced signals appear in phase with the peaks of hard X-ray emission as observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and mostly trace the position of RHESSI hard X-ray footpoint sources. (4) in four zones, it takes place co-temporally with real magnetic changes which persist after the flare. Only for the other two zones does the flux density recover to the pre-flare level immediately after the flare. The physical implications of the flare-induced signal are discussed in view of its relevance to the non-thermal electron precipitation and primary energy release in the flare. Title: Magnetic interactions during sympathetic solar eruptions Authors: Jiang, Yun-Chun; Bi, Yi; Yang, Jia-Yan; Zheng, Rui-Sheng; Wang, Jing-Xiu Bibcode: 2009RAA.....9..603J Altcode: We present the first evidence for occurrences of magnetic interactions between a jet, a filament and coronal loops during a complex event, in which two flares sequentially occurred at different positions of the same active region and were closely associated with two successive coronal mass ejections (CMEs), respectively. The coronal loops were located outside but nearby the filament channel before the flares. The jet, originating from the first flare during its rise phase, not only hit the filament body but also met one of the ends of the loops. The filament then underwent an inclined eruption followed by the second flare and met the same loop end once more. Both the jet and the filament eruption were accompanied by the development of loop disturbances and the appearances of brightenings around the meeting site. In particular, the erupting filament showed clear manifestations of interactions with the loops. After a short holdup, only its portion passed through this site, while the other portion remained at the same place. Following the filament eruption and the loop disappearance, four dimmings were formed and located near their four ends. This is a situation that we define as “quadrupolar dimmings." It appears that the two flares consisted of a sympathetic pair physically linked by the interaction between the jet and the filament, and their sympathy indicated that of the two CMEs. Moreover, it is very likely that the two sympathetic CMEs were simultaneously associated with the disappearing loops and the quadrupole dimmings. Title: On VI Emission in Nuclear Region of NGC 1068 Authors: Zheng, W.; Kriss, G. A.; Wang, J. -X.; Sahnow, D.; Allen, M.; Dopita, M.; Tsvetanov, Z.; Bicknell, G. Bibcode: 2009AIPC.1135...52Z Altcode: FUSE Spectra of the nuclear region of NGC 1068 find strong OVI emission consisting of a pair of narrow and broad components. There is a gradient in the velocity field for the narrow O VI component of ~200 kms-1 from ~2'' southwest of the nucleus to ~4'' northeast. A similar pattern is also observed with the broad O VI component, with a gradient of ~3000 kms-1. These results are consistent with the HST/STIS findings and suggest a biconical structure in which the velocity field is mainly radial outflow. Title: The application of the LAMBDA method in the estimation of the GPS slant wet vapour Authors: Huang, S. Q.; Wang, J. X.; Wang, X. Y.; Chen, J. P. Bibcode: 2009AcASn..50...60H Altcode: By far, the technology of GPS data processing has been improved well and the accuracy of this processing has increased greatly. So, GPS has been applied in meteorology widely.The SWV (Slant Wet Vapour) is a very important parameter in the GPS meteorology. In 2004, Song Shuli had advanced a SWV estimation method which used the precision orbit of JPL, IGS clock and the LC observations without cycle-slip. But this method is bad in real-time character. LAMBDA method, which is working well in the VRS (Virtual Reference Station) /COORS, is used in the ambiguity estimation. The method was proved by some true data calculation. The ZTD(Zenith Time Delay), which is calculated by projecting SWD (Slant Wet Delay) to zenith direction, has good coherence. Compairing the ZTD with the results of GAMIT and BERNESE, the deviation between our result and the GAMIT one is commonly little than 3cm, and the BERNESE one is commonly little than 1.5cm. Title: Commission 10: Solar Activity Authors: Klimchuk, James A.; van Driel-Gesztelyi, Lidia; Schrijver, Carolus J.; Melrose, Donald B.; Fletcher, Lyndsay; Gopalswamy, Natchimuthuk; Harrison, Richard A.; Mandrini, Cristina H.; Peter, Hardi; Tsuneta, Saku; Vršnak, Bojan; Wang, Jing-Xiu Bibcode: 2009IAUTA..27...79K Altcode: 2008arXiv0809.1444K Commission 10 deals with solar activity in all of its forms, ranging from the smallest nanoflares to the largest coronal mass ejections. This report reviews scientific progress over the roughly two-year period ending in the middle of 2008. This has been an exciting time in solar physics, highlighted by the launches of the Hinode and STEREO missions late in 2006. The report is reasonably comprehensive, though it is far from exhaustive. Limited space prevents the inclusion of many significant results. The report is divided into the following sections: Photosphere and chromosphere; Transition region; Corona and coronal heating; Coronal jets; flares; Coronal mass ejection initiation; Global coronal waves and shocks; Coronal dimming; The link between low coronal CME signatures and magnetic clouds; Coronal mass ejections in the heliosphere; and Coronal mass ejections and space weather. Primary authorship is indicated at the beginning of each section. Title: Relativistic Outflows in Two Quasars in the Chandra Deep Field South Authors: Zheng, Z. Y.; Wang, J. X. Bibcode: 2008ApJ...688..116Z Altcode: 2008arXiv0807.4669Z In this paper we provide new 1 Ms Chandra ACIS spectra of two quasars in the Chandra Deep Field South (CDF-S) which had strong and extremely blueshifted X-ray emission/absorption line features in previous 1 Ms spectra, with outflowing bulk velocity v ~ 0.65-0.84c. In the new 1 Ms spectra, the relativistic blueshifted line feature is solidly confirmed in CXO CDFS J033225.3-274219 (CDFS 46, z = 1.617), and marginally visible in CXO CDFS J033260.0-274748 (CDFS 11, z = 2.579), probably due to the increased Chandra ACIS background in the new 1 Ms exposure. The new data rule out the possibility (although very tiny already based on the old 1Ms data) that the two sources were selected to be unusual due to noise spikes in the spectra. The only likely interpretation is extremely blueshifted iron absorption/emission lines or an absorption edge due to relativistic outflow. We find that the rest-frame emission line center in CDFS 46 marginally decreased from 16.2 to 15.2 keV after 7 years. The line shift could be due to either a decreasing outflowing velocity or a lower ionization level. Including the two quasars reported in this paper, we collect a total of 7 quasars from the literature showing blueshifted emission or absorption line features with v >= 0.4c in X-ray spectra, and discuss their connection to jet and/or BAL (broad absorption line) outflows. Title: A magnetic null geometry reconstructed from Cluster spacecraft observations Authors: He, J. -S.; Tu, C. -Y.; Tian, H.; Xiao, C. -J.; Wang, X. -G.; Pu, Z. -Y.; Ma, Z. -W.; Dunlop, M. W.; Zhao, H.; Zhou, G. -P.; Wang, J. -X.; Fu, S. -Y.; Liu, Z. -X.; Zong, Q. -G.; Glassmeier, K. -H.; Reme, H.; Dandouras, I.; Escoubet, C. P. Bibcode: 2008JGRA..113.5205H Altcode: This paper reports for the first time the identification of a magnetic structure around a magnetic null in a magnetic reconnection region in the magnetotail. Magnetic reconnection is one of the fundamental processes in astrophysical and solar-terrestrial plasmas. Though the concept of reconnection has been studied for many years, the process that really occurs has not been fully revealed by direct measurements. In particular, the lack of a description of three-dimensional (3-D) reconnecting magnetic field from observations makes the task more difficult. The Cluster spacecraft array provide an opportunity to reconstruct the 3-D magnetic reconnection structure based on magnetic field vectors simultaneously measured at four positions. The identification of this structure comes from a new method of analysis of in situ measurements proposed here. Applying a fitting model of 10 spherical harmonic functions and a Harris current sheet function, plus a constant field, we reconstruct a 3-D magnetic field configuration around the magnetic null in an reconnection event observed by Cluster in the geo-magnetotail. Title: Determination of the Topology Skeleton of Magnetic Fields in a Solar Active Region Authors: Zhao, Hui; Wang, Jing-Xiu; Zhang, Jun; Xiao, Chi-Jie; Wang, Hai-Min Bibcode: 2008ChJAA...8..133Z Altcode: 2007arXiv0712.3319Z Magnetic topology has been a key to the understanding of magnetic energy release mechanism. Based on observed vector magnetograms, we have determined the three-dimensional (3D) topology skeleton of the magnetic fields in the active region NOAA 10720. The skeleton consists of six 3D magnetic nulls and a network of corresponding spines, fans, and null-null lines. For the first time, we have identified a spiral magnetic null in Sun's corona. The magnetic lines of force twisted around the spine of the null, forming a `magnetic wreath' with excess of free magnetic energy and resembling observed brightening structures at extra-ultraviolet (EUV) wavebands. We found clear evidence of topology eruptions which are referred to as catastrophic changes of topology skeleton associated with a coronal mass ejection (CME) and an explosive X-ray flare. These results shed new lights on the structural complexity and its role in explosive magnetic activity. The concept of flux rope has been widely used in modelling explosive magnetic activity, although their observational identity is rather obscure or, at least, lacking of necessary details up to date. We suggest that the magnetic wreath associated with the 3D spiral null is likely an important class of the physical entity of flux ropes. Title: Chandra X-Ray Sources in the LALA Cetus Field Authors: Wang, J. X.; Zheng, Z. Y.; Malhotra, S.; Finkelstein, S. L.; Rhoads, J. E.; Norman, C. A.; Heckman, T. M. Bibcode: 2007ApJ...669..765W Altcode: 2007arXiv0707.3239W The 174 ks Chandra Advanced CCD Imaging Spectrometer exposure of the Large Area Lyman Alpha Survey (LALA) Cetus field is the second of the two deep Chandra images on LALA fields. In this paper we present the Chandra X-ray sources detected in the Cetus field, along with an analysis of X-ray source counts, stacked X-ray spectrum, and optical identifications. A total of 188 X-ray sources were detected: 174 in the 0.5-7.0 keV band, 154 in the 0.5-2.0 keV band, and 113 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with LALA field (172 ks exposure). Interestingly, we find consistent hard-band X-ray source density, but (36+/-12)% higher soft-band X-ray source density in Cetus field. The weighted stacked spectrum of the detected X-ray sources can be fitted by a power law with photon index Γ=1.55. Based on the weighted stacked spectrum, we find that the resolved fraction of the X-ray background drops from (72+/-1)% at 0.5-1.0 keV to (63+/-4)% at 6.0-8.0 keV. The unresolved spectrum can be fitted by a power law over the range 0.5-7 keV, with a photon index Γ=1.22. We also present optical counterparts for 154 of the X-ray sources, down to a limiting magnitude of r'=25.9 (Vega), using a deep r'-band image obtained with the MMT.

Optical Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. Title: Nuclear Obscuration in Seyfert 2 Galaxies with and without Polarized Broad Emission Lines Authors: Shu, X. W.; Wang, J. -X.; Jang, P.; Fan, L. L.; Wang, T. -G. Bibcode: 2007ASPC..373..507S Altcode: We compiled a sample of 54 Seyfert 2 galaxies with both spectropolarimetric and X-ray observations to investigate the role of nuclear obscuration in the visibility of polarized broad emission lines (PBL). We find that at L[O III] > 1041 ergs s-1, Seyfert 2 galaxies without PBL are more obscured in X-ray (at a confidence level of 99%). Our results explain the non-detections of PBL under the framework of the unified model, and put strong constraint on the geometry of the obscuring torus and the scattering region. Title: On the X-ray Baldwin Effect for the Narrow Fe Kα Emission Line Authors: Jiang, P.; Wang, J. -X.; Wang, T. -G. Bibcode: 2007ASPC..373..143J Altcode: We build a large AGN sample with narrow FeK line measurements by combining the archival Chandra HETG observations of 34 type 1 AGNs with XMM-Newton observations in literature. We find a similar X-ray Baldwin effect as reported earlier by Page et al. in the sample; however, we note that the anti-correlation is dominated by the radio-loud AGN in the sample, whose X-ray spectra might be contaminated by the relativistic jet. Excluding the radio-loud AGN, we find a much weaker anti-correlation. We present Monte Carlo simulations showing that such a weak anti-correlation can be attributed to the relative short time scale variations of the X-ray continuum. Title: Polarization of Quasars: Rotated and Funnel-shaped Outflow Authors: Wang, H. -Y.; Wang, T. -G.; Wang, J. -X. Bibcode: 2007ASPC..373..335W Altcode: 2006astro.ph.12339W Polarization is a useful probe to investigate the geometries and dynamics of outflows in BAL QSOs. We perform a Monte Carlo simulation to calculate the polarization produced by resonant and electron scattering in BALR. We find: 1) A rotated and funnel-shaped outflow is preferred to explain many observed polarization features. 2) Resonant scattering can contribute a significant part of the N V emission line in some QSOs. Title: Satellite observations of separator-line geometry of three-dimensional magnetic reconnection Authors: Xiao, C. J.; Wang, X. G.; Pu, Z. Y.; Ma, Z. W.; Zhao, H.; Zhou, G. P.; Wang, J. X.; Kivelson, M. G.; Fu, S. Y.; Liu, Z. X.; Zong, Q. G.; Dunlop, M. W.; Glassmeier, K. -H.; Lucek, E.; Reme, H.; Dandouras, I.; Escoubet, C. P. Bibcode: 2007NatPh...3..609X Altcode: 2007arXiv0705.1021X Detection of a separator line that connects magnetic nulls and the determination of the dynamics and plasma environment of such a structure can improve our understanding of the three-dimensional (3D) magnetic reconnection process. However, this type of field and particle configuration has not been directly observed in space plasmas. Here we report the identification of a pair of nulls, the null-null line that connects them, and associated fans and spines in the magnetotail of the Earth using data from the four Cluster spacecraft. With di and de designating the ion and electron inertial lengths, respectively, the separation between the nulls is found to be ~0.7+/-0.3di and an associated oscillation is identified as a lower-hybrid wave with wavelength ~de. This in situ evidence of the full 3D reconnection geometry and associated dynamics provides an important step towards establishing an observational framework of 3D reconnection. Title: A Catastrophic Flux Rope in a Quadrupole Magnetic Field for Coronal Mass Ejections Authors: Zhang, Y. -Z.; Wang, J. -X. Bibcode: 2007ApJ...663..592Z Altcode: We propose a flux-rope model for the initiation of flare-associated CMEs. The model triggers the eruption with a catastrophic loss of MHD equilibrium and then requires magnetic reconnection to sustain the eruption's acceleration. We carry out 2.5-dimensional time-dependent resistive MHD simulations, choosing the initial state such that a flux rope embedded in a quadrupole field is attached to the solar surface; we then increase the magnetic flux of the rope by two different amounts, thus obtaining two cases. One exhibits a gradual acceleration of the flux rope, whereas the other produces an immediate acceleration. In both cases, the maximum speed of the flux rope is representative of a fast CME. Thus, we conclude that the flux-rope dynamics depends on the intensity of the emergent magnetic flux. Our model does reproduce the three-component structure of CMEs. Title: A Study of the Periodicities of Solar Filament Activity Authors: Song, Wen-bin; Wang, Jing-xiu Bibcode: 2007ChA&A..31..270S Altcode: Using the filament catalogues of Meudon Observatory, France, we have compiled a daily count sequence of filaments from July 1957 to December 2004 and carried out a periodicity analysis with the Scargle periodogram and Morlet wavelet transform. It is discovered that this sequence exhibits four evident periods: 1557, 1141, 795 and 367 days. The characteristics of the variations of these periods are analyzed in detail and the phases, physical mechanisms as well as the mutual relations of some of the periods are briefly discussed. Title: A dynamo model for axisymmetric and non-axisymmetric solar magnetic fields Authors: Jiang, J.; Wang, J. X. Bibcode: 2007MNRAS.377..711J Altcode: 2007astro.ph..2508J; 2007MNRAS.tmp..253J More and more observations are showing a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. Its existence indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric α2-Ω dynamo model is derived to explore the characteristics of the axisymmetric (m = 0) and the first non-axisymmetric (m = 1) modes and to provide a theoretical basis with which to explain the `active longitude', `flip-flop' and other non-axisymmetric phenomena. The model consists of an updated solar internal differential rotation, a turbulent diffusivity varying with depth, and an α-effect working at the tachocline in a rotating spherical system. The difference between the α2-Ω and the α-Ω models and the conditions that favour the non-axisymmetric modes under solar-like parameters are also presented. Title: Determination of the νe and total B8 solar neutrino fluxes using the Sudbury Neutrino Observatory Phase I data set Authors: Aharmim, B.; Ahmad, Q. R.; Ahmed, S. N.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Bühler, G.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bergevin, M.; Bigu, J.; Biller, S. D.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cameron, J.; Chan, Y. D.; Chen, H. H.; Chen, M.; Chen, X.; Cleveland, B. T.; Cowan, J. H. M.; Cowen, D. F.; Cox, G. A.; Currat, C. A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Deng, H.; Dimarco, M.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Fleurot, F.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Gagnon, N.; Germani, J. V.; Gil, S.; Goldschmidt, A.; Goon, J. T. M.; Graham, K.; Grant, D. R.; Guillian, E.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A. S.; Hamian, A. A.; Handler, W. B.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Henning, R.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howard, C.; Howe, M. A.; Huang, M.; Hykaway, J. G.; Isaac, M. C. P.; Jagam, P.; Jamieson, B.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P. T.; Kirch, K.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kormos, L. L.; Kos, M.; Kouzes, R.; Krüger, A.; Kraus, C.; Krauss, C. B.; Kutter, T.; Kyba, C. C. M.; Labranche, H.; Lange, R.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Loach, J. C.; Locke, W.; Luoma, S.; Lyon, J.; MacLellan, R.; Majerus, S.; Mak, H. B.; Maneira, J.; Marino, A. D.; Martin, R.; McCauley, N.; McDonald, A. B.; McDonald, D. S.; McFarlane, K.; McGee, S.; McGregor, G.; Drees, R. Meijer; Mes, H.; Mifflin, C.; Miknaitis, K. K. S.; Miller, M. L.; Milton, G.; Moffat, B. A.; Monreal, B.; Moorhead, M.; Morrissette, B.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Nickel, B. G.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; Oblath, N. S.; Okada, C. E.; O'Keeffe, H. M.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Ott, R.; Peeters, S. J. M.; Poon, A. W. P.; Prior, G.; Reitzner, S. D.; Rielage, K.; Roberge, A.; Robertson, B. C.; Robertson, R. G. H.; Rosendahl, S. S. E.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schülke, A.; Schwendener, M. H.; Secrest, J. A.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W. E.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Stonehill, L. C.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Takeuchi, Y.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P. M.; Tolich, N.; Trent, P. T.; Tserkovnyak, Y. I.; Tsui, T.; Tunnell, C. D.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Walker, T. J.; Wall, B. L.; Waltham, C. E.; Tseung, H. Wan Chan; Wang, J. -X.; Wark, D. L.; Wendland, J.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters, J. M.; Wright, A.; Yeh, M.; Zuber, K. Bibcode: 2007PhRvC..75d5502A Altcode: 2006nucl.ex..10020S This article provides the complete description of results from the Phase I data set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is based on a 0.65 kiloton-year exposure of 2H2O (in the following denoted as D2O) to the solar B8 neutrino flux. Included here are details of the SNO physics and detector model, evaluations of systematic uncertainties, and estimates of backgrounds. Also discussed are SNO's approach to statistical extraction of the signals from the three neutrino reactions (charged current, neutral current, and elastic scattering) and the results of a search for a day-night asymmetry in the νe flux. Under the assumption that the B8 spectrum is undistorted, the measurements from this phase yield a solar νe flux of ϕ(νe)=1.76-0.05+0.05(stat.)-0.09+0.09(syst.)×106 cm-2 s-1 and a non-νe component of ϕ(νμτ)=3.41-0.45+0.45(stat.)-0.45+0.48(syst.)×106 cm-2 s-1. The sum of these components provides a total flux in excellent agreement with the predictions of standard solar models. The day-night asymmetry in the νe flux is found to be Ae=7.0±4.9(stat.)-1.2+1.3%(syst.), when the asymmetry in the total flux is constrained to be zero. Title: Magnetic Properties of Metric Noise Storms Associated with Coronal Mass Ejections Authors: Wen, Ya-Yuan; Wang, Jing-Xiu; Zhang, Yu-Zong Bibcode: 2007ChJAA...7..265W Altcode: Using Nançay Radioheliograph (NRH) imaging observations, combined with SOHO/Michelson Doppler Imager (MDI) magnetogram observations and coronal magnetic field extrapolation, we studied the magnetic nature of metric noise storms that are associated with coronal mass ejections (CMEs). Four events are selected: the events of 2000 July 14, 2001 April 26, 2002 August 16 and 2001 March 28. The identified noise storm sources cover or partially cover the active regions (ARs), but the centers of storm sources are offset from the ARs. Using extrapolated magnetic field lines, we find that the noise storm sources trace the boundary between the open and closed field lines. We demonstrate that the disappearance of noise storm source is followed by the appearance of the burst source. The burst sources spread on the solar disk and their distributions correspond to the extent of the CME in LASCO C2 field of view. All the SOHO/Extreme Ultraviolet Imaging Telescope (EIT) dimmings associated with noise storm sources are located at the periphery of noise storms where the magnetic lines of force were previously closed and low-lying. When the closed field becomes partially or fully open, the basic configurations of noise storm sources are changed, then the noise storm sources are no longer observed. These observations provide the information that the variations of noise storms manifest the restructuring or reconfiguring of the coronal magnetic field. Title: Investigating the Nuclear Obscuration in Two Types of Seyfert 2 Galaxies Authors: Shu, X. W.; Wang, J. X.; Jiang, P.; Fan, L. L.; Wang, T. G. Bibcode: 2007ApJ...657..167S Altcode: 2006astro.ph..3338S We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical spectropolarimetric and X-ray data available, in which 29 of the Sy2s have a detection of polarized broad emission lines (PBLs) and 25 do not. We find that for luminous Sy2s with L[OIII>1041 ergs s-1, sources with PBLs have smaller X-ray absorption column densities in comparison to those without PBLs (at a 92.3% confidence level): most of the Sy2s with NH<1023.8 cm-2 show PBLs (86%; 12 out of 14), while the fraction is much smaller for sources with heavier obscuration (54%; 15 out of 28). The confidence level of the difference in absorption bounces up to 99.1% when using the thickness (``T'') ratio (F2-10keV/F[OIII) as an indicator. We rule out observation or selection bias as the origin for the difference. Our results, for the first time with high statistical confidence, show that, in additional to the activity of the nuclei, the nuclear obscuration also plays an important role in the visibility of PBLs in Sy2s. These results can be interpreted in the framework of the unified model. We can reach these results in the unified model if (1) the absorption column density is higher at large inclinations and (2) the scattering region is obscured at large inclinations. Title: Most Hard-X-Ray-Selected Quasars in the Chandra Deep Fields are Obscured Authors: Wang, J. X.; Jiang, P.; Zheng, Z. Y.; Tozzi, P.; Norman, C.; Giacconi, R.; Gilli, R.; Hasinger, G.; Kewley, L.; Mainieri, V.; Nonino, M.; Rosati, P.; Streblyanska, A.; Szokoly, G.; Zirm, A.; Zheng, W. Bibcode: 2007ApJ...657...95W Altcode: 2006astro.ph.11251W Measuring the population of obscured quasars is one of the key issues in understanding the evolution of active galactic nuclei (AGNs). With a redshift completeness of 99%, the X-ray sources detected in the Chandra Deep Field South (CDF-S) provide the best sample for this issue. In this paper, we study the population of obscured quasars in CDF-S by choosing the 4-7 keV selected sample, which is less biased by the intrinsic X-ray absorption. The 4-7 keV band-selected samples also filter out most of the X-ray-faint sources with too few counts, for which the measurements of NH and LX have very large uncertainties. Simply adopting the best-fit L2-10 keV and NH, we find that 71%+/-19% (20 out of 28) of the quasars (with intrinsic L2-10 keV>1044 ergs s-1) are obscured with NH>1022 cm-2. Taking into account the uncertainties in the measurements of both NH and LX, conservative lower and upper limits for the fraction are 54% (13 out 24) and 84% (31 out 37). In the Chandra Deep Field North, the number is 29%; however, this is mainly due to the redshift incompleteness. We estimate a fraction of ~50%-63% after correcting for the redshift incompleteness with a straightforward approach. Our results robustly confirm the existence of a large population of obscured quasars. Title: Commission 10: Solar Activity Authors: Melrose, Donald B.; Klimchuk, James A.; Benz, A. O.; Craig, I. J. D.; Gopalswamy, N.; Harrison, R. A.; Kozlovsky, B. Z.; Poletto, G.; Schrijver, K. J.; van Driel-Gesztelyi, L.; Wang, J. -X. Bibcode: 2007IAUTA..26...75M Altcode: Commission 10 aims at the study of various forms of solar activity, including networks, plages, pores, spots, fibrils, surges, jets, filaments/prominences, coronal loops, flares, coronal mass ejections (CMEs), solar cycle, microflares, nanoflares, coronal heating etc., which are all manifestation of the interplay of magnetic fields and solar plasma. Increasingly important is the study of solar activities as sources of various disturbances in the interplanetary space and near-Earth "space weather".Over the past three years a major component of research on the active Sun has involved data from the RHESSI spacecraft. This review starts with an update on current and planned solar observations from spacecraft. The discussion of solar flares gives emphasis to new results from RHESSI, along with updates on other aspects of flares. Recent progress on two theoretical concepts, magnetic reconnection and magnetic helicity is then summarized, followed by discussions of coronal loops and heating, the magnetic carpet and filaments. The final topic discussed is coronal mass ejections and space weather.The discussions on each topic is relatively brief, and intended as an outline to put the extensive list of references in context.The review was prepared jointly by the members of the Organizing Committee, and the names of the primary contributors to the various sections are indicated in parentheses. Title: Eruption of an Active-Region Filament Driven by an Emerging Bipole Authors: Jiang, Yun-Chun; Shen, Yuan-Deng; Wang, Jing-Xiu Bibcode: 2007ChJAA...7..129J Altcode: A section of an S-shaped filament underwent an eruption in a sigmoidal active region (AR 8027) with S-shaped coronal structure, which was clearly driven by a bipole emerging below the NW end of the filament. The bipole with two separating poles showed typical characteristics of emerging flux region (EFR) and its axis rotated counterclockwise. Two cancelling magnetic features (CMFs) were formed between the two poles and adjacent flux with opposite polarity and substantial flux cancellation occurred in them. Along with the bipole emergence the filament was strongly disturbed. Just before the filament eruption, two X-ray loops overlying the filament brightened, an axial X-ray structure and then a cusp structure appeared. During the eruption first the whole filament rose and then its SE end broke away from the chromosphere, while its NW end remained stationary. Helical structure and motion were observed in the filament body and downward mass motion in the two ends. After the eruption, a major part of the filament remained and slowly returned to quiescence, and an X-ray arcade and an axial structure formed. These observations suggest that the eruption resulted from the interaction between the bipole and the overlying loops. We provide evidence that steady photospheric reconnection between their footprints took place in the two CMFs during the bipole emergence. Title: VizieR Online Data Catalog: X-ray properties of AGN in CDFS (Tozzi+, 2006) Authors: Tozzi, P.; Gilli, R.; Mainieri, V.; Norman, C.; Risaliti, G.; Rosati, P.; Bergeron, J.; Borgani, S.; Giacconi, R.; Hasinger, G.; Nonino, M.; Streblyanska, A.; Szokoly, G.; Wang, J. X.; Zheng, W. Bibcode: 2007yCat..34510457T Altcode: We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS, J/ApJS/139/369) taking advantage of optical spectroscopy and photometric redshifts for 321 extragalactic sources out of the total sample of 347 sources. As a default spectral model, we adopt a power law with slope Gamma with an intrinsic redshifted absorption NH, a fixed Galactic absorption and an unresolved Fe emission line. For 82 X-ray bright sources, we are able to perform the X-ray spectral analysis leaving both Gamma and NH free.

(1 data file). Title: Periodicities in solar filament activity Authors: Song, W. B.; Wang, J. X. Bibcode: 2007AcASn..48...29S Altcode: By using the Meudon filament catalogues we reconstruct a daily sequence of filament counts from July 1957 to December 2004 and perform a periodicity analysis with the methods of Scargle periodogram and Morlet wavelet transform. As a result, four prominent periods are found around 1557, 1141, 795 and 367 days. We analyze their temporal variabilities in detail and discuss some typical ones' phases, physical implications and mutual relations briefly. Title: Two Successive Coronal Mass Ejections Driven by the Kink and Drainage Instabilities of an Eruptive Prominence Authors: Zhou, G. P.; Wang, J. X.; Zhang, J.; Chen, P. F.; Ji, H. S.; Dere, K. Bibcode: 2006ApJ...651.1238Z Altcode: We describe a clear case of the initiation of a propagating bright arc and a CME on 2002 December 28, which were associated with an eruptive prominence. In EIT 304 and 195 Å images, a very long filament showed evidence of severe twisting in one of its fragments, which appeared as a prominence on December 26; then, the prominence showed the conversion of its twist into writhe. Two days later, the prominence displayed a slow rising motion for hours. Internal twisting and mass motion took place before the rapid acceleration and final eruption. The propagating bright arc and the following CME corresponded to the early rising and the subsequently eruptive phases of the prominence, respectively. Signatures of magnetic reconnection, i.e., a cusp structure and postflare loops in EUV wave bands and hard X-ray sources in the corona, were observed after the prominence eruption. It appears that the kink instability and the mass drainage in the prominence played key roles in triggering the initiation of the CME. However, the rather impulsive acceleration of the CME resulted from magnetic reconnection beneath the filament. Title: 3D Topology Structure of Coronal Magnetic Field Authors: Zhao, H.; Wang, J. X.; Zhang, J.; Xiao, C. J. Bibcode: 2006IAUJD...3E..40Z Altcode: We use the Poincaré index of isolated null-points in vector field to strictly identify 3D null-points in coronal magnetic fields reconstructed from the observed vector magnetogram of several important active regions. Base on the null-points we identified, we reveal the essential topology skeletons of 3D coronal magnetic fields. Comparing these topology skeletons with images of H-alpha, EIT, TRACE and X-ray, we find 3D topology structures of coronal magnetic fields are closely associated with solar flares and CMEs. We also find indication of 3D magnetic reconnection by studying temporal series of 3D topology structures of solar magnetic fields. To thoroughly investigate 3D topology structures of coronal magnetic fields is a key to understand the physical mechanism of solar activity. Title: On the Fraction of X-Ray-obscured Quasars in the Local Universe Authors: Wang, J. X.; Jiang, P. Bibcode: 2006ApJ...646L.103W Altcode: 2006astro.ph..6333W Recent wide-area hard X-ray and soft gamma-ray surveys have shown that the fraction of X-ray-obscured active galactic nuclei (AGNs) in the local universe significantly decreases with intrinsic luminosity. In this Letter we point out that two corrections have to be made to the samples: (1) radio-loud AGNs have to be excluded, since their X-ray emission might be dominated by the jet component, and (2) Compton-thick sources have to be excluded too, since their hard X-ray and soft gamma-ray emission are also strongly attenuated by Compton scattering. The soft gamma-ray-selected AGN samples obtained by Swift and INTEGRAL provide the best opportunity to study the fraction of obscured AGNs in the local universe in the least biased way. We choose these samples to check if the corrections could alter the above result on the fraction of obscured AGNs. We find that before the corrections both samples show significant anticorrelation between LX and NH, indicating an obvious decrease in the fraction of obscured AGNs with luminosity. However, after the corrections, we find only marginal evidence of anticorrelation (at the 98% confidence level) in the Swift sample and no evidence at all in the INTEGRAL sample, which consists of a comparable number of objects. We conclude that current samples only show a marginal decrease in the fraction of obscured AGNs in the local universe and that much larger samples are required in order to reach a more robust conclusion. Title: Solar radiation pressure models for the GPS satellites Authors: Chen, J. P.; Wang, J. X. Bibcode: 2006AcASn..47..310C Altcode: The largest error in currently used for GPS orbit models is due to the effect of solar radiation pressure (SRP). Over the last a few years many improvement were made in modeling the orbits of GPS satellites within the IGS. One of the most important factors for the improvement is the perfect of SRP models. The main SRP models currently used for GPS satellites is presented. Using different models, it can get the performance of the models in satellite orbit determining. The results show that new models developed by Bern University gain almost an order of magnitude better than that of the other traditional models. Title: In situ evidence for the structure of the magnetic null in a 3D reconnection event in the Earth's magnetotail Authors: Xiao, C. J.; Wang, X. G.; Pu, Z. Y.; Zhao, H.; Wang, J. X.; Ma, Z. W.; Fu, S. Y.; Kivelson, M. G.; Liu, Z. X.; Zong, Q. G.; Glassmeier, K. H.; Balogh, A.; Korth, A.; Reme, H.; Escoubet, C. P. Bibcode: 2006NatPh...2..478X Altcode: 2006physics...6014X Magnetic reconnection is one of the most important processes in astrophysical, space and laboratory plasmas. Identifying the structure around the point at which the magnetic field lines break and subsequently reform, known as the magnetic null point, is crucial to improving our understanding of reconnection. But owing to the inherently three-dimensional nature of this process, magnetic nulls are only detectable through measurements obtained simultaneously from at least four points in space. Using data collected by the four spacecraft of the Cluster constellation as they traversed a diffusion region in the Earth's magnetotail on 15 September 2001, we report here the first in situ evidence for the structure of an isolated magnetic null. The results indicate that it has a positive-spiral structure whose spatial extent is of the same order as the local ion inertial length scale, suggesting that the Hall effect could play an important role in 3D reconnection dynamics. Title: On the X-Ray Baldwin Effect for Narrow Fe Kα Emission Lines Authors: Jiang, P.; Wang, J. X.; Wang, T. G. Bibcode: 2006ApJ...644..725J Altcode: 2006astro.ph..3339J Most active galactic nuclei (AGNs) exhibit a narrow Fe Kα line at ~6.4 keV in the X-ray spectra, due to the fluorescent emission from cold material far from the inner accretion disk. Using XMM-Newton observations, Page et al. found that the equivalent width (EW) of the narrow Fe Kα line decreases with increasing luminosity (EW~L-0.17+/-0.08), suggesting a decrease in the covering factor of the material emitting the line (presumably the torus). By combining the archival Chandra HETG observations of 34 type 1 AGNs with XMM observations in the literature, we build a much larger sample with 101 AGNs. We find a similar X-ray Baldwin effect in the sample (EW~L-0.2015+/-0.0426) however, we note that the anticorrelation is dominated by the radio-loud AGNs in the sample, whose X-ray spectra might be contaminated by the relativistic jet. Excluding the radio-loud AGNs, we find a much weaker anticorrelation (EW~L-0.1019+/-0.0524). We present Monte Carlo simulations showing that such a weak anticorrelation can be attributed to the relative short timescale variations of the X-ray continuum. Title: Catastrophic Behavior of Multiple Coronal Flux Rope System Authors: Ding, J. Y.; Hu, Y. Q.; Wang, J. X. Bibcode: 2006SoPh..235..223D Altcode: A major solar active event called Bastille Day Event occurred in AR 9077 on July 14, 2000. Simultaneous occurrence of a filament eruption, a flare and a coronal mass ejection was observed in this event. Previous analyses of this event show that before the event, there existed an activation and eruption of a huge trans-equatorial filament, which might play a crucial role in triggering the Bastille Day event. This implies that independent flux systems are closely related to and affect each other, which has encouraged us to investigate the catastrophic behavior of a multiple coronal flux rope system with the use of a 2.5-D time-dependent MHD model. A force-free field that contains three separate coronal flux ropes is taken to be the initial state. Starting from this state, we increase either the annular or the axial flux of a certain flux rope to examine the catastrophic behavior of the system in two regimes, the ideal MHD regime and the resistive MHD regime. It is found that a catastrophe occurs if the flux exceeds a certain critical value, or the magnetic energy of the system exceeds a certain threshold: the rope of interest breaks away from the base and escapes to infinity, leaving a current sheet below. Moreover, the destiny of the remainder flux ropes relies on whether reconnection takes place across the current sheet. In the ideal MHD regime, i.e., in the absence of reconnection, these ropes remain to be attached to the base in equilibrium, whereas in the resistive MHD regime they abruptly erupt upward during reconnection and escape to infinity. Reconnection causes the field lines to close back to the base and thus changes the background field outside the attached flux ropes in such a way that the constraint on these ropes is substantially relaxed and the corresponding catastrophic energy threshold is reduced accordingly, leading to a catastrophic eruption of these ropes. Since magnetic reconnection is generally inevitable when a current sheet forms and develops through an eruption of one flux rope, the eruption of this flux rope must lead to an eruption of the others. This provides an example to demonstrate the interaction between several independent magnetic flux systems in different regions, as implied by the Bastille Day event, and may serve as a possible mechanism for sympathetic events occurring on the Sun. Title: X-ray spectral properties of active galactic nuclei in the Chandra Deep Field South Authors: Tozzi, P.; Gilli, R.; Mainieri, V.; Norman, C.; Risaliti, G.; Rosati, P.; Bergeron, J.; Borgani, S.; Giacconi, R.; Hasinger, G.; Nonino, M.; Streblyanska, A.; Szokoly, G.; Wang, J. X.; Zheng, W. Bibcode: 2006A&A...451..457T Altcode: 2006astro.ph..2127T We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS) taking advantage of optical spectroscopy and photometric redshifts for 321 extragalactic sources out of the total sample of 347 sources. As a default spectral model, we adopt a power law with slope Γ with an intrinsic redshifted absorption N_H, a fixed Galactic absorption and an unresolved Fe emission line. For 82 X-ray bright sources, we are able to perform the X-ray spectral analysis leaving both Γ and NH free. The weighted mean value for the slope of the power law is < Γ > ≃ 1.75 ± 0.02, and the distribution of best fit values shows an intrinsic dispersion of σ_int ≃ 0.30. We do not find hints of a correlation between the spectral index Γ and the intrinsic absorption column density N_H. We then investigate the absorption distribution for the whole sample, deriving the NH values in faint sources by fixing Γ = 1.8. We also allow for the presence of a scattered component at soft energies with the same slope of the main power law, and for a pure reflection spectrum typical of Compton-thick AGN. We detect the presence of a scattered soft component in 8 sources; we also identify 14 sources showing a reflection-dominated spectrum. The latter are referred to as Compton-thick AGN candidates. By correcting for both incompleteness and sampling-volume effects, we recover the intrinsic NH distribution representative of the whole AGN population, f(N_H) dN_H, from the observed one. f(N_H) shows a lognormal shape, peaking around log(N_H)≃ 23.1 and with σ ≃ 1.1. Interestingly, such a distribution shows continuity between the population of Compton-thin and that of Compton-thick AGN. We find that the fraction of absorbed sources (with N_H>1022 cm-2) in the sample is constant (at the level of about 75%) or moderately increasing with redshift. Finally, we compare the optical classification to the X-ray spectral properties, confirming that the correspondence of unabsorbed (absorbed) X-ray sources to optical type I (type II) AGN is accurate for at least 80% of the sources with spectral identification (1/3 of the total X-ray sample). Title: A Non-axisymmetric Spherical α2-Dynamo Authors: Jiang, Jie; Wang, Jing-Xiu Bibcode: 2006ChJAA...6..227J Altcode: Using the Chebyshev-tau method, the generation of oscillatory non-axisymmetric stellar magnetic fields by the α2-dynamo is studied in spherical geometry. Following the boundary conditions given by Schubert & Zhang, the spherical α2-dynamo consists of a fully convective spherical shell with inner radius ri and outer radius ro. A comparison of the critical dynamo numbers of axisymmetric and phi-dependent modes for different thicknesses of the convective shell and different α-profiles leads to the following qualitative results: (i) when the angular factor of α-profile is sinnθ cos θ (n = 1,2,4) the solutions of the α2-dynamo are oscillatory and non-axisymmetric, (ii) the thinner the convective shell, the more easily is the non-axisymmetric mode excited and the higher is the latitudinal wave number, (iii) the thickness of the outer convective shell has an effect on the symmetries of the magnetic fields. Title: Two-Current-Sheet Reconnection Model of Interdependent Flare and Coronal Mass Ejection Authors: Zhang, Y. Z.; Wang, J. X.; Hu, Y. Q. Bibcode: 2006ApJ...641..572Z Altcode: 2006astro.ph..1231Z Time-dependent resistive magnetohydrodynamic simulations are carried out to study a flux rope eruption caused by magnetic reconnection with implication in coexistent flare-CME (coronal mass ejection) events. An early result obtained in a recent analysis of double catastrophe of a flux rope system is used as the initial condition, in which an isolated flux rope coexists with two current sheets: a vertical one below and a transverse one above the flux rope. The flux rope erupts when reconnection takes place in the current sheets, and the flux rope dynamics depends on the reconnection sequence in the two current sheets. Three cases are discussed: reconnection occurs (1) simultaneously in the two current sheets, (2) first in the transverse one and then in the vertical one, and (3) in an order opposite that of case 2. Such a two-current-sheet reconnection exhibits characteristics of both magnetic breakout for CME initiation and the standard flare model. We argue that both breakout-like and tether-cutting reconnections could be important for CME eruptions and associated surface activities. Title: Transequatorial Filament Eruption and Its Link to a Coronal Mass Ejection Authors: Wang, Jing-Xiu; Zhou, Gui-Ping; Wen, Ya-Yuan; Zhang, Yu-Zong; Wang, Hua-Ning; Deng, Yuan-Yong; Zhang, Jun; Harra, Louise K. Bibcode: 2006ChJAA...6..247W Altcode: We revisit the Bastille Day flare/CME Event of 2000 July 14, and demonstrate that this flare/CME event is not related to only one single active region (AR). Activation and eruption of a huge transequatorial filament are seen to precede the simultaneous filament eruption and flare in the source active region, NOAA AR 9077, and the full halo-CME in the high corona. Evidence of reconfiguration of large-scale magnetic structures related to the event is illustrated by SOHO EIT and Yohkoh SXT observations, as well as, the reconstructed 3D magnetic lines of force based on the force-free assumption. We suggest that the AR filament in AR 9077 was connected to the transequatorial filament. The large-scale magnetic composition related to the transequatorial filament and its sheared magnetic arcade appears to be an essential part of the CME parent magnetic structure. Estimations show that the filament-arcade system has enough magnetic helicity to account for the helicity carried by the related CMEs. In addition, rather global magnetic connectivity, covering almost all the visible range in longitude and a huge span in latitude on the Sun, is implied by the Nançay Radioheliograph (NRH) observations. The analysis of the Bastille Day event suggests that although the triggering of a global CME might take place in an AR, a much larger scale magnetic composition seems to be the source of the ejected magnetic flux, helicity and plasma. The Bastille Day event is the first described example in the literature, in which a transequatorial filament activity appears to play a key role in a global CME. Many tens of halo-CME are found to be associated with transequatorial filaments and their magnetic environment. Title: Large-scale source regions of earth-directed coronal mass ejections Authors: Zhou, G. P.; Wang, J. X.; Zhang, J. Bibcode: 2006A&A...445.1133Z Altcode: Based on SOHO/MDI, EIT, Yohkoh/SXT, Hα, and other relevant observations, we analyzed all the earth-directed halo coronal mass ejections (CMEs) in the interval from Mar. 1997 to Dec. 2003. A total of 288 earth-directed CMEs were studied and their associated surface activity events identified. Unlike the previous studies that often attributed a surface activity event or a given active region to a CME source region, this statistical analysis puts emphasis on the large-scale magnetic structures of CMEs, in which the CME-associated surface activity takes place. All the CMEs are found to be associated with large-scale source structures. The identified large-scale structures can be grouped into four different categories: extended bipolar regions (EBRs), transequatorial magnetic loops, transequatorial filaments and their associated magnetic structures, and long filaments along the boundaries of EBRs. The relative percentages of their associated CMEs are 36%, 40%, 13%, and 11%, respectively. The analysis indicates that CMEs are intrinsically associated with source magnetic structures on a large spatial scale. Title: Interaction Between CME and Magnetosphere Observed by Cluster on Nov. 6, 2001: (1) Waves Excitation Authors: Xiao, C. J.; Song, L. T.; Pu, Z. Y.; Wang, J. X.; Liu, Z. X.; Glassmeier, K. -H.; Balogh, A.; Reme, H. Bibcode: 2006IAUS..233..373X Altcode: Very few in situ measurements so far show the details of the interactions between CME and magnetosphere. Here we report a fortuitous observation that the Cluster spacecraft were located at the dusk-side magnetopause, meandering back and forth four times between the ICME and the magnetosphere, and observed part process of the interaction between the CME and the magnetosphere. The primarily analysis showed that: (1) a fast ion beam other than the ambient plasma was observed almost perpendicular to the magnetic field; (2) The left-hand-polarized kinetic Alfvén waves excitation by the ion beam; and (3) the resonances between the kinetic Alfvén waves and part of the beam particles lead to the pitch angle diffusion of resonant particles and formating of a monospheric distribution with nearly constant kinetic energy. The wave-particle resonance may pay an important role in the energy transfer and particle exchange across the magnetopause between the magnetosheath and magnetosphere during the CME impulsion. Title: A Non-axisymmetric Solar Dynamo Model Authors: Jiang, J.; Wang, J. X. Bibcode: 2006cosp...36..814J Altcode: 2006cosp.meet..814J Increasing observations are becoming available about a weak but persistent non-axisymmetric magnetic field co-exist with the dominant axisymmetric field on the Sun It indicates non-axisymmetric magnetic fields play an important role in the origin of solar activities A nonlinear non-axisymmetric dynamo model is applied to try to give an explanation of this phenomenon The model is characterized by a solar-like internal differential rotation profile distribution of turbulent diffusivity and the nonlinear alpha-quench in spherical coordinate r theta phi Only the modes m 0 and 1 are considered and numerically solved as an eigenvalue problem The stable solutions can be found The distributions of the non-axisymmetric part of the surface fields and the magnetic energies as a function of time for the two modes are given too Title: CMEs driven by an eruptive prominence Authors: Zhou, G. P.; Wang, J. X.; Zhang, J.; Chen, P. F.; Ji, H. S.; Dere, K. Bibcode: 2006IAUS..233..405Z Altcode: A clear case on Dec. 28 2002 is presented. It is about the initiation of two successive CMEs, which were related to an eruptive prominence. In EIT 304 Å and 195 Å observations, we found a long filament severely twisting in a piece of its fragments, which appeared as a prominence on Dec. 26. Then, the prominence converted its twist into writhe. Two days later, the prominence displayed a slow rising motion for hours. There happened internal twisting and mass motion before the prominence rapid acceleration and final eruption. Two successive CMEs recorded by LASCO C2 coronagraph corresponded to the early rising and the subsequently eruptive phases of the prominence, respectively. Evidence of magnetic reconnection, i.e., a cusp structure and post-flare loops in EUV wavebands, and hard X-ray sources in the corona, were observed after the prominence disruption. It appears that the kink instability and the mass drainage in the prominence played important roles in triggering two CMEs' initiation. We suspected that the rather impulsive acceleration of the second CME resulted from magnetic reconnection beneath the prominence. Title: The acceleration error estimates in LASCO CME measures Authors: Wen, Y. Y.; Wang, J. X.; Maia, D.; Zhao, H. Bibcode: 2006cosp...36.1147W Altcode: 2006cosp.meet.1147W Based on the paper that the error estimates for the height measures grows rather fast in the first few solar radii and becomes reasonably flat above 5 solar radii We show here how to obtain reliable acceleration error estimates for the measures given in the catalog We show that for the fast CMEs the uncertainties in the accelerations are quite large when compared with the average variation within a particular velocity subgroup of CMEs and as such only events with very high acceleration can reliably be considered as accelerated For most events one can not decide if a particular event has positive or negative acceleration As a consequence and classification that separates CMEs according to acceleration criteria will find similar distributions for accelerated and decelerated CMEs but that only reflects the fact that the error in determining the acceleration is quit high On average we find that slower CMEs tend to have a positive acceleration about 1 m s 2 at heights above 5 solar radii while the 5 faster CMEs show an average negative acceleration about -2 5 m s 2 as they propagate from 5 to 30 solar radii Title: MHD Numerical Simulation of Interdependent Flares and CMEs Authors: Zhang, Y. Z.; Wang, J. X.; Hu, Y. Q. Bibcode: 2006IAUS..233..130Z Altcode: Using time-dependent resistive magnetohydrodynamic simulations, we study a flux rope eruption caused by magnetic reconnection with implication in coexistent flare-CME events. Without the resistance the flux rope system presents a double catastrophe. We use the first catastrophic state as the initial condition, in which an isolated flux rope coexists with two current sheets: a vertical one below and a transverse one above the flux rope. The flux rope erupts when reconnection starts in the current sheets, and the flux rope dynamics depends on the reconnection sequence in the two current sheets. We obtain three cases: reconnection occurs (1) simultaneously in the two current sheets, (2) first in the transverse one and then in the vertical, and (3) in an order opposite to case 2. Such a model exhibits characteristics of both magnetic breakout model for CME initiation and standard flare model. We argue that both breakout-like and tether-cutting reconnections may be important for CME eruptions. Title: High-precision polarimetry design for Space Solar Telescope Authors: Zhang, Z. Y.; Deng, Y. Y.; Hu, K. L.; Wang, D. G.; Lin, J. B.; Sun, Y. Z.; Wang, J. X. Bibcode: 2006cosp...36.2864Z Altcode: 2006cosp.meet.2864Z High polarization accuracy and high spatial resolution measurement of solar magnetic field is the most important mission of Space Solar Telescope Although there is no seeing induced error in the outer space the mass flow and evolution in the solar atmosphere may become the main source of false polarization signals To reduce this source of polarization errors a high-speed polarimetry is required In this paper we present our newly designed polarimeter based on high-speed electro-optical modulation We employ Mueller Matrix to analyses the polarization characteristics of optical elements and evaluate the polarization errors By these discussions we also determine the requirements to the imaging process system of SST Title: Solar proton spectrum and acceleration during the 20 January 2005 flare Authors: Wang, R. G.; Wang, J. X. Bibcode: 2006cosp...36.1856W Altcode: 2006cosp.meet.1856W A extreme solar cosmic ray event was broken out on 20 January 2005 It was not only the most intense solar energetic particle SEP event measured by GOES satellites since 1976 but also the largest ground level enhancement GLE recorded in neutron monitors since 1956 We present the solar proton energy spectra of this event data from GOES measurements in multi-channels of energy These spectra are well fit by a double power law form It was shown that the January 20 event had the hardest energy spectrum during solar cycle 23 and the highest fluxes for above 30 MeV protons in past 30 years We examine variations of the spectral index from -1 4 to -0 8 within the rise phase of proton intensity Combing X-ray radio emission and CME observation as well as available neutron monitor data relativistic proton acceleration and travel is discussed It seems to imply that the first arrival relativistic protons are released in low corona and accelerated up to GeV within minutes This impulsive high energy process more likely associated with solar flare instead of CME Title: Large geomagnetic storms of extreme solar event periods in solar cycle 23 Authors: Wang, R. G.; Wang, J. X. Bibcode: 2006cosp...36.1855W Altcode: 2006cosp.meet.1855W At the duration of extreme solar events solar eruption associated with big flares or and energetic coronal mass ejections CMEs can not only make high energy particles acceleration but also give rise to large geomagnetic storms which have significant effects on the Earth s environment and human life Around 14 solar cosmic ray ground level enhancement GLE events in solar cycle 23 we examine the cosmic ray variations solar wind speeds ion densities interplanetary magnetic fields and geomagnetic disturbance storm time indices Dst We find that all but one of GLEs are always followed by a geomagnetic storm with Dst leq -50 nT within 1-5 days later Most 10 14 geomagnetic storms have Dst index leq -100 nT suggesting that GLE event prediction of geomagnetic storms is 93 for moderate storms and 71 for large storms More than half 57 Dst depressions are simultaneously accompanied by cosmic ray decreases and other Dst variabilities are without clear cosmic ray deceases We also investigated the interplanetary plasma features during GLE events Most geomagnetic storm correspond significant periods of southward B z and in close to 80 of the cases that the B z was first northward then turning southward after storm sudden commencement SSC Plasma flow speed ion number density and interplanetary plasma temperature near 1 AU also have a peak at interplanetary shock arrival Solar cause and energetic particle signatures of large geomagnetic storms are discussed Title: Homologous emerging flux and associated solar activity Authors: Zhou, G. P.; Wang, J. X. Bibcode: 2006cosp...36.2906Z Altcode: 2006cosp.meet.2906Z There are 69 GOES X-ray flares produced in the active regions ARs 10486 and 10488 during the famous Oct -Nov 2003 solar event Among them the X28 flare in AR10488 on Nov 04 2003 may have been the largest X-ray event since observations began in 1976 Part of the associated large flare CMEs form magnetic clouds in the interplanetary space By investigating the photosphere magnetograms we find that the emerging flux in AR10486 10488 10489 10491 and 10492 appear homologous The homologous behaviors are further confirmed by the evidence from the sub-photospheric flow maps vertical velocity and meridional vorticity as well as these ARs evolutions in MDI synoptic charts We also find that there is large-scale magnetic connectivity among these ARs whether from EIT images or from the global magnetic force lines reconstructed by the potential extrapolation which indicate these referred ARs are not isolated each other The ARs are probably involved in a same topological magnetic system since we find a predominant negative helicity sign in these ARs and their associated magnetic clouds With more analysis on the other observations in TRACE RHESSI GOES and so on it is speculated that the associated flares CMEs initiate during the evolutions of this topological isolated magnetic system especially when it interacted with the other environmental flux Title: The detection of "magnetic element"---why we need an one-meter Space Solar Telescope Authors: Deng, Y. Y.; Wang, J. X.; Ai, G. X. Bibcode: 2006cosp...36..942D Altcode: 2006cosp.meet..942D The nature of magnetic element the elemental structure of solar magnetic field is one of the most important mysteries in solar physics The intrinsic properties of magnetic element such as field strength filling factor spatial scale are unknown yet though the history of solar magnetic measurement can go back to one hundred years ago With the development of technology solar physicists have made a lots of attempts to resolve the magnetic element directly For example with the help of a set of techniques adaptive optics correlation tracker image reconstruction etc the one-meter Swedish Solar Telescope in the Canary Islands has nearly reached its diffraction-limit resolution sim 0 18 630 25nm which roughly match the spatial-scale requirement of magnetic element detection However none current-used telescope can resolve magnetic element at this moment yet as spatial resolution is just one of the requirements of magnetic element detection In this paper the requirements of magnetic element detection will be discussed By these discussions we know that the spatial resolution temporal resolution and magnetic sensitivity are all important The proposed Space Solar Telescope an one-meter Chinese space telescope can match these requirements Title: Solar 3He-rich events and abnormal enhancements of heavy-ion isotopes accelerated in two stages Authors: Zhang, T. X.; Wang, J. X.; Tan, A. Bibcode: 2005JGRA..11012111Z Altcode: Heating and acceleration of neon (20Ne), magnesium (24Mg), and their rare isotopes (22Ne and 26Mg) in solar 3He-rich events are investigated according to the two-stage acceleration mechanism. It is shown that 20Ne+8, 22Ne+9, 24Mg+10, and 26Mg+11 can be preferentially heated by H-cyclotron waves with a frequency close to twice the 3He-cyclotron frequency that also heat 3He, through the third harmonic cyclotron resonance. If the initial electron temperature is in the range of ∼2-10 MK, the abundance ratios 22Ne/20Ne and 26Mg/24Mg in high-energy particles due to the second-stage acceleration can be enhanced by a factor of ∼2-6 relative to the solar corona, which are consistent with the measurements of the University of Maryland particle instrument on the Solar Anomalous and Magnetospheric Particle Explorer and the Ultra Lower Energy Isotope Spectrometer particle instrument on the Advanced Composition Explorer. Title: A New Method of Identifying 3D Null Points in Solar Vector Magnetic Fields Authors: Zhao, Hui; Wang, Jing-Xiu; Zhang, Jun; Xiao, Chi-Jie Bibcode: 2005ChJAA...5..443Z Altcode: Employing the Poincaré index of isolated null-points in a vector field, we worked out a mathematical method of searching for 3D null-points in coronal magnetic fields. After introducing the relevant differential topology, we test the method by using the analytical model of Brown & Priest. The location of null-point identified by our method coincides precisely with the analytical solution. Finally we apply the method to the 3D coronal magnetic fields reconstructed from an observed MDI magnetogram of a super-active region (NOAA 10488). We find that the 3D null-point seems to be a key element in the magnetic topology associated with flare occurrence. Title: Relativistic Outflow in CXOCDFS J033260.0-274748 Authors: Wang, J. X.; Wang, T. G.; Tozzi, P.; Giacconi, R.; Hasinger, G.; Kewley, L.; Mainieri, V.; Nonino, M.; Norman, C.; Streblyanska, A.; Szokoly, G.; Yaqoob, T.; Zirm, A. Bibcode: 2005ApJ...631L..33W Altcode: 2005astro.ph..8225W In this Letter we report the detection of a strong and extremely blueshifted X-ray absorption feature in the 1 Ms Chandra spectrum of CXOCDFS J033260.0-274748, a quasar at z=2.579 with L2-10keV~4×1044 ergs s-1. The broad absorption feature at ~6.3 keV in the observed frame can be fitted either as an absorption edge at 20.9 keV or as a broad absorption line at 22.2 keV rest frame. The absorber has to be extremely ionized with an ionization parameter ξ~104, and a high column density, NH>5×1023 cm-2. We reject the possibility of a statistical or instrumental artifact. The most likely interpretation is an extremely blueshifted broad absorption line or absorption edge, due to H or He-like iron in a relativistic jetlike outflow with bulk velocity of ~0.7c-0.8c. Similar relativistic outflows have been reported in the X-ray spectra of several other AGNs in the past few years. Title: Progress in the studies on a relic solar magnetic field Authors: Song, Wen-Bin; Wang, Jing-Xiu Bibcode: 2005PABei..23..205S Altcode: It is really possible that the Sun possesses a relic magnetic field of the pre-main sequence epoch in its radiative core. Due to a stably stratified fluid and an extremely high electrical conductivity in the solar interior, a relic solar magnetic field can survive for a very long time. A relic field can help us to explain many asymmetries in solar activities, such as the north-south asymmetries of solar magnetic activities, active longitudes and holes, low-latitude coronal holes, Maunder minimum, etc. In addition it can affect the distribution and evolution of solar surface magnetic field by changing the boundary conditions of solar dynamo. This paper focuses on the introduction of recent progress and issues in observations and theories of relic solar magnetic field. Some unresolved problems and highlights are also discussed. Title: A study of the north-south asymmetry of solar photospheric magnetic flux Authors: Song, Wen-bin; Wang, Jing-xiu; Ma, Xia Bibcode: 2005ChA&A..29..274S Altcode: 2005ChA&A..29..274W Statistical characteristics of the variation of the North-South asymmetry of solar photospheric magnetic flux in 1978-2002 are systematically studied, and they are found to be related to the cycle of solar activity. The degree of the asymmetry during the minimum of solar activity is obviously higher than that during the maximum of solar activity. Moreover, the change of magnetic flux is always accompanied by a gradual shift of dominance from the northern hemisphere in the ascending phase to the southern hemisphere in the descending phase. A wavelet transform is used to make a detailed probe of possible periodicities in the variation of the North-South asymmetry. Title: Resonant Heating of Ions by Parallel Propagating Alfvén Waves in Solar Coronal Holes Authors: Zhang, Tian-Xi; Wang, Jing-Xiu; Xiao, Chi-Jie Bibcode: 2005ChJAA...5..285Z Altcode: Resonant heating of H, O+5, and Mg+9 by parallel propagating ion-cyclotron Alfvén waves in solar coronal holes at a heliocentric distance is studied using the heating rate derived from the quasilinear theory. It is shown that the particle-Alfvén-wave interaction is a significant microscopic process. The temperatures of the ions are rapidly increased up to the observed order in only microseconds, which implies that simply inserting the quasilinear heating rate into the fluid/MHD energy equation to calculate the radial dependence of ion temperatures may cause errors as the time scales do not match. Different species ions are heated by Alfvén waves with a power law spectrum in approximately a mass order. To heat O+5 over Mg+9 as measured by the Ultraviolet Coronagraph Spectrometer (UVCS) in the solar coronal hole at a region gtrsim1.9Rodot, the energy density of Alfvén waves with a frequency close to the O+5-cyclotron frequency must be at least double of that at the Mg+9-cyclotron frequency. With an appropriate wave-energy spectrum, the heating of H, O+5 and Mg+9 can be consistent with the UVCS measurements in solar coronal holes at a heliocentric distance. Title: VizieR Online Data Catalog: Chandra Deep Field-South: Optical spectroscopy (Szokoly+, 2004) Authors: Szokoly, G. P.; Bergeron, J.; Hasinger, G.; Lehmann, I.; Kewley, L.; Mainieri, V.; Nonino, M.; Rosati, P.; Giacconi, R.; Gilli, R.; Gilmozzi, R.; Norman, C.; Romaniello, M.; Schreier, E.; Tozzi, P.; Wang, J. X.; Zheng, W.; Zirm, A. Bibcode: 2005yCat..21550271S Altcode: We present the results of our spectroscopic follow-up program of the X-ray sources detected in the 942ks exposure of the Chandra Deep Field-South (CDFS). A total of 288 possible counterparts were observed at the VLT with the FORS1/FORS2 spectrographs for 251 of the 349 Chandra sources (including three additional faint X-ray sources). Spectra and R-band images are shown for all the observed sources and R-K colors are given for most of them. Spectroscopic redshifts were obtained for 168 X-ray sources, of which 137 have both reliable optical identification and redshift estimate (including 16 external identifications). The R<24 observed sample comprises 161 X-ray objects (181 optical counterparts), and 126 of them have unambiguous spectroscopic identification.

(4 data files). Title: Double Catastrophe of Coronal Flux Rope in Quadrupolar Magnetic Field Authors: Zhang, Y. Z.; Hu, Y. Q.; Wang, J. X. Bibcode: 2005ApJ...626.1096Z Altcode: Using a relaxation method based on time-dependent ideal magnetohydrodynamic simulations, we find 2.5-dimensional force-free field solutions in spherical geometry, which are associated with an isolated flux rope embedded in a quadrupolar background magnetic field. The background field is of Antiochos type, consisting of a dipolar and an octopolar component with a neutral point somewhere in the equatorial plane. The flux rope is characterized by its magnetic fluxes, including the annular flux Φp and the axial magnetic flux Φϕ, and its geometric features described by the height of the rope axis and the length of the vertical current sheet below the rope. It is found that for a given Φp, the force-free field exhibits a complex catastrophic behavior with respect to increasing Φϕ. There exist two catastrophic points, and the catastrophic amplitude, measured by the jump in the height of the rope axis, is finite for both catastrophes. As a result, the flux rope may levitate stably in the corona after catastrophe, with a transverse current sheet above and a vertical current sheet below. The magnetic energy threshold for the two successive catastrophes are found to be larger than the corresponding partly open field energy. We argue that it is the transverse current sheet formed above the flux rope that provides a downward Lorentz force on the flux rope and thus keeps the rope levitating stably in the corona. Title: Progress in solar dynamo theories Authors: Jiang, Jie; Wang, Jing-Xiu Bibcode: 2005PABei..23..121J Altcode: The solar dynamo, which explains the origin and the evolution of all magnetic fields observed on the sun, is the fundamental and essential question of Solar Physics. Scientific inquiry into the question is more than an academic exercise. It is important to the development of space technology and the prediction of terrestrial climate. With the development of helioseismology, the solar dynamo has made great progresses. Staring from the observation, the paper summarizes some observations on the solar surface and the dynamic construction interior. The basic theories and the central models are introduced. Some unsolved problems are discussed. Title: Two Extreme Double-peaked Line Emitters in the Sloan Digital Sky Survey Authors: Wang, T. -G.; Dong, X. -B.; Zhang, X. -G.; Zhou, H. -Y.; Wang, J. -X.; Lu, Y. -J. Bibcode: 2005ApJ...625L..35W Altcode: 2005astro.ph..4320W Double-peaked Balmer lines have been observed in about 150 active galactic nuclei and were interpreted preferentially as emission from relativistic accretion disks. We report the discovery of extreme double-peaked lines in SDSS J0942+0900 and SDSS J1417+6141. The FWHM of the Hα line, ~=40,600 km s-1, in the first object is almost twice as large as the broadest previously known. By comparing the line profile with accretion disk models, we find that most of the line flux is emitted from a narrow annulus around 100rg in SDSS J0942+0900, and from a disk with radii between 100rg and 400rg in SDSS J1417+6141. This is the first time that an accretion disk at radii below 100rg has been directly probed through optical emission lines. A certain asymmetry in the disk is required for both objects. Another, much weaker, broad Hα component (Wλ~20 Å and FWHM ~4000 km s-1) is also detected in both objects. Both objects show weak radio emission and strong high-ionization narrow lines. Title: VizieR Online Data Catalog: Photometric redshifts of X-ray sources in CDF-S (Zheng+, 2004) Authors: Zheng, W.; Mikles, V. J.; Mainieri, V.; Hasinger, G.; Rosati, P.; Wolf, C.; Norman, C.; Szokoly, G.; Gilli, R.; Tozzi, P.; Wang, J. X.; Zirm, A.; Giacconi, R. Bibcode: 2005yCat..21550073Z Altcode: Based on the photometry of 10 near-ultraviolet, optical, and near-infrared bands of the Chandra Deep Field-South, we estimate the photometric redshifts for 342 X-ray sources, which constitute ~99% of all the detected X-ray sources in the field.

(1 data file). Title: Correlation Heights of the Sources of Solar Ultraviolet Emission Lines in a Quiet-Sun Region Authors: Tu, Chuan-Yi; Zhou, Cheng; Marsch, Eckart; Wilhelm, Klaus; Zhao, Liang; Xia, Li-Dong; Wang, Jing-Xiu Bibcode: 2005ApJ...624L.133T Altcode: The radiance and Doppler-velocity maps of the emission lines of Si II, C IV, and Ne VIII obtained in a quiet region of the Sun by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) are correlated with the vertical component, Bz, of the magnetic field vector as extrapolated, by means of a force-free field model, from the photospheric magnetic field measured by MDI (Michelson Doppler Imager). It is found that, with increasing vertical height, each of the correlation coefficients initially increases to a maximum value before it decreases again. The height corresponding to this maximum is called the correlation height. For the data sets selected from a quiet-Sun region, the correlation heights of Si II and C IV are near 2 Mm, and for Ne VIII near 4 Mm. At their correlation heights, the averaged square root of the radiance of the emission lines of Si II and C IV, considered as a proxy of the plasma density, has a linear relationship with Bz. This result supports the empirical concept that the solar transition region is very thin and still affected by frozen-in convection. A way for improvement of such studies is also outlined. Title: Solar Wind Origin in Coronal Funnels Authors: Tu, Chuan-Yi; Zhou, Cheng; Marsch, Eckart; Xia, Li-Dong; Zhao, Liang; Wang, Jing-Xiu; Wilhelm, Klaus Bibcode: 2005Sci...308..519T Altcode: The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested. Title: An Overdensity of Lyα Emitters at Redshift z~5.7 near the Hubble Ultra Deep Field Authors: Wang, J. X.; Malhotra, S.; Rhoads, J. E. Bibcode: 2005ApJ...622L..77W Altcode: 2005astro.ph..1479W We have identified an obvious and strong large-scale structure at redshift z~5.75 in a wide (31'×33') field, narrowband survey of the Chandra Deep Field-South region. This structure is traced by 17 candidate Lyα emitters, among which 12 are found in an 823 nm filter (corresponding to Lyα at z=5.77+/-0.03) and five in an 815 nm image (z=5.70+/-0.03). The Lyα emitters in both redshift bins are concentrated in one quadrant of the field. The Hubble Ultra Deep Field, the Chandra Deep Field-South, and the Great Observatories Origins Deep Survey-South fields all lie near the edge of this overdensity region. Our results are consistent with reports of an overdensity in the Ultra Deep Field region at z~5.9. This structure is the highest redshift overdensity found so far. Title: Strong Ca II Absorption Lines in the Reddened Quasar SDSS J2339-0912: Evidence of the Collision/Merger in the Host Galaxy? Authors: Wang, T. G.; Dong, X. B.; Zhou, H. Y.; Wang, J. X. Bibcode: 2005ApJ...622L.101W Altcode: 2005astro.ph..4319W We report the detection of strong Ca II/Mg II absorption lines at the quasar redshift in the narrow-line quasar SDSS J2339-0912 (z=0.6604). The quasar exhibits strong Fe II, a small Balmer emission line width, and a very red B-Ks color. Both the optical continuum and broad emission lines are reddened by SMC-like dust of E(B-V)~=1.0 mag, while its near-infrared color (J-Ks=1.60) shows little reddening. The Ca II absorption lines are saturated and resolved with an FWHM of 362 km s-1 and an equivalent width of WCaIIK=4.2 Å (in the source rest frame). Mg II absorption lines are also saturated and have a similar line width. The line profile and the fact that there is no evidence of starlight from the host galaxy suggest that these absorption lines are not of a stellar origin. The ratio of column density of Ca II to that of dust is consistent with that of the interstellar medium (ISM) in our Galaxy. We suggest that both the heavy reddening and the large absorption line width are due to the highly disturbed ISM on the line of sight toward the quasar and that the disturbance is caused by a galaxy collision or even merger in the quasar host galaxy. Title: Cross-correlations between CMEs and other Solar Activity Indices Authors: Song, W. B.; Wang, J. X. Bibcode: 2005IAUS..226..213S Altcode: Using the list of CMEs observed by SOHO/LASCO, we compile a daily CME counts from January 1996 to December 2003. Cross-correlations between the CME counts and other three solar activity indices, i.e., flare index, sunspot number, and photospheric magnetic flux, are examined in both real and Fourier spaces. We find that correlations are all significant in real space, but only photospheric magnetic flux has good correlation with CME counts in Fourier space. Typical periods of CME occurrence are presented and discussed. Title: CMEs and Flux Appearance in the Periphery of Two Unipolar Sunspots Authors: Yang, X. L.; Song, W. B.; Zhou, G. P.; Zhang, J.; Wang, J. X. Bibcode: 2005IAUS..226..215Y Altcode: A class of large-scale magnetic compositions have been identified to be CME-prolific, which is characterized by a huge unipolar sunspot appearing in a large-scale extended bipolar region in synoptic magnetic charts. To understand the CMEs' origin and the nature of flux appearance, we scrutinize the long time-sequence of MDI magnetograms of high-resolution mode for super active region AR9236. Two types of magnetic features are clearly identified. They are moving magnetic features (MMFs) emanated radially from the penumbral boundary and emerging flux regions (EFRs) whose growing opposite polarities rotate out from the inner boundary of sunspot moat along helical paths in opposite directions. The interaction between the MMFs and EFRs often creates multi-fold magnetic neutral lines where the flare/CMEs initiated. Title: The north-south asymmetry of solar photospheric magnetic flux Authors: Song, W. B.; Wang, J. X.; Ma, X. Bibcode: 2005AcASn..46...19S Altcode: The north-south asymmetry of solar photospheric magnetic flux is studied during years 1978-2002, finding that it has been relative to the solar activity cycle and peaked about the time of solar minimum. The dominance of solar activity has started to shift during the solar maximum from the northern hemisphere to the southern one. And its periodicities have been also discussed in detail with the wavelet transform. Title: Wavelet analysis of photospheric magnetic flux Authors: Song, W. B.; Wang, J. X. Bibcode: 2005AdSpR..35..341S Altcode: We link 342 NSO/Kitt Peak synoptic charts during 1978 to 2003 one by one in time order and reconstruct a daily sequence of photospheric magnetic flux (PMF). By using wavelet transform (WT) some typical mid-term periodicities of PMF are identified, such as 1.38-year, 332-, 275- and 158-day periods. We discuss briefly their temporal evolutions and mutual relations in this paper. For a comparison with another solar general index, we also analyze the periodicities of total solar irradiance (TSI) with the same method. We find the wavelet power spectra of such two sequences are very similar. Therefore, we think PMF and TSI may have some common physical origins. Title: The Chandra Deep Field-South: Optical Spectroscopy. I. Authors: Szokoly, G. P.; Bergeron, J.; Hasinger, G.; Lehmann, I.; Kewley, L.; Mainieri, V.; Nonino, M.; Rosati, P.; Giacconi, R.; Gilli, R.; Gilmozzi, R.; Norman, C.; Romaniello, M.; Schreier, E.; Tozzi, P.; Wang, J. X.; Zheng, W.; Zirm, A. Bibcode: 2004ApJS..155..271S Altcode: 2003astro.ph.12324S We present the results of our spectroscopic follow-up program of the X-ray sources detected in the 942 ks exposure of the Chandra Deep Field-South (CDFS). A total of 288 possible counterparts were observed at the VLT with the FORS1/FORS2 spectrographs for 251 of the 349 Chandra sources (including three additional faint X-ray sources). Spectra and R-band images are shown for all the observed sources and R-K colors are given for most of them. Spectroscopic redshifts were obtained for 168 X-ray sources, of which 137 have both reliable optical identification and redshift estimate (including 16 external identifications). The R<24 observed sample comprises 161 X-ray objects (181 optical counterparts), and 126 of them have unambiguous spectroscopic identification. There are two spikes in the redshift distribution, predominantly populated by type 2 active galactic nuclei (AGNs) but also type 1 AGN and X-ray normal galaxies: the one at z=0.734 is fairly narrow (in redshift space) and comprises two clusters/groups of galaxies centered on extended X-ray sources, the second one at z=0.674 is broader and should trace a sheetlike structure. The type 1 and type 2 populations are clearly separated in X-ray/optical diagnostics involving parameters sensitive to absorption/reddening: X-ray hardness ratio (HR), optical/near-IR color, soft X-ray flux, and optical brightness. Nevertheless, these two populations cover similar ranges of hard X-ray luminosity and absolute K magnitude, thus trace similar levels of gravitational accretion. Consequently, we introduce a new classification based solely on X-ray properties, HR, and X-ray luminosity, consistent with the unified AGN model. This X-ray classification uncovers a large fraction of optically obscured, X-ray-luminous AGNs missed by the classical optical classification. We find a similar number of X-ray type 1 and type 2 QSOs [LX(0.5-10keV)>1044 ergs s-1] at z>2 (13 sources with unambiguous spectroscopic identification); most X-ray type 1 QSOs are bright, R<~24, whereas most X-ray type 2 QSOs have R>~24, which may explain the difference with the CDFN results as few spectroscopic redshifts were obtained for R>24 CDFN X-ray counterparts. There are X-ray type 1 QSOs down to z~0.5, but a strong decrease at z<2 in the fraction of luminous X-ray type 2 QSOs may indicate a cosmic evolution of the X-ray luminosity function of the type 2 population. An X-ray spectral analysis is required to confirm this possible evolution. The red color of most X-ray type 2 AGNs could be due to dust associated with the X-ray absorbing material and/or a substantial contribution of the host galaxy light. The latter can also be important for some redder X-ray type 1 AGNs. There is a large population of EROs (R-K>5) as X-ray counterparts, and their fraction strongly increases with decreasing optical flux, up to 25% for the R>=24 sample. They cover the whole range of X-ray hardness ratios, comprise objects of various classes (in particular a high fraction of z>~1 X-ray absorbed AGNs, but also elliptical and starburst galaxies) and more than half of them should be fairly bright X-ray sources [LX(0.5-10keV)>1042 ergs s-1]. Photometric redshifts will be necessary to derive the properties and evolution of the X-ray selected EROs.

Based on observations collected at the European Southern Observatory, Chile [ESO no. 66.A-0270(A) and 67.A-0418(A)]. Title: Low frequency radio signatures of coronal mass ejections Authors: Wen, Ya-Yuan; Wang, Jing-Xiu Bibcode: 2004PABei..22..284W Altcode: Coronal mass ejections (CMEs) are the most spectacular phenomena of solar activities, and the solar events with the largest spatial scale. CMEs are often accompanied with other solar activities. Many solar phenomena are believed to have direct or indirect correlations with CMEs, such as solar flares, prominence eruption, helmet streamers, high-speed solar winds, coronal and interplanetary shock waves, and so on. Radio observations are an important complementary tool to study CMEs. Multi-frequency radio measurements not only study the initiation of CMEs, but also get more information on triggering mechanism of CMEs. In the present paper, we summarize the relationships between CMEs and low frequency radio bursts with the observational instruments and the radio signatures of CMEs being introduced and analyzed. The initiation mechanism and some open questions are discussed as well. Finally we claim that studies of CMEs must base on the multi-species data in all electromagnetic radiation wavelengths. Title: Photometric Redshift of X-Ray Sources in the Chandra Deep Field-South Authors: Zheng, W.; Mikles, V. J.; Mainieri, V.; Hasinger, G.; Rosati, P.; Wolf, C.; Norman, C.; Szokoly, G.; Gilli, R.; Tozzi, P.; Wang, J. X.; Zirm, A.; Giacconi, R. Bibcode: 2004ApJS..155...73Z Altcode: 2004astro.ph..6482Z Based on the photometry of 10 near-ultraviolet, optical, and near-infrared bands of the Chandra Deep Field-South, we estimate the photometric redshifts for 342 X-ray sources, which constitute ~99% of all the detected X-ray sources in the field. The models of spectral energy distribution are based on galaxies and a combination of power-law continuum and emission lines. Color information is useful for source classifications: type I active galactic nuclei (AGNs) show nonthermal spectral features that are distinct from galaxies and type II AGNs. The hardness ratio in X-ray and the X-ray-to-optical flux ratio are also useful discriminators. Using rudimentary color separation techniques, we are able to further refine our photometric redshift estimations. Among these sources, 173 have reliable spectroscopic redshifts, which we use to verify the accuracy of photometric redshifts and to modify the model inputs. The average relative dispersion in redshift distribution is ~8%, among the most accurate for photometric surveys. The high reliability of our results is attributable to the high quality and broad coverage of data as well as the applications of several independent methods and a careful evaluation of every source. We apply our redshift estimations to study the effect of redshift on broadband colors and to study the redshift distribution of AGNs. Our results show that both the hardness ratio and U-K color decline with redshift, which may be the result of a K-correction. The number of type II AGNs declines significantly at z>2 and that of galaxies declines at z>1. However, the distribution of type I AGNs exhibits less redshift dependence. As well, we observe a significant peak in the redshift distribution at z=0.6. We demonstrate that our photometric redshift estimation produces a reliable database for the study of X-ray luminosity of galaxies and AGNs.

Based on observations performed at the European Southern Observatory and observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities of Research in Astronomy, Inc., under NASA contract NAS5-26555. Title: Double-Power-Law Energy Spectra of Electrons from Solar 3He-rich Events Authors: Zhang, T. X.; Wang, J. X. Bibcode: 2004ApJ...613L.165Z Altcode: A possible explanation is proposed for the double-power-law energy spectrum of electrons from solar 3He-rich events. According to the two-stage acceleration model that was developed by Zhang for the heating and acceleration of ions and electrons in solar 3He-rich events, the energy spectrum of electrons in the thermal to power law energy range is derived. It is shown that the electron flux generally includes a thermal component at low energies and a nonthermal component with a power-law spectrum at high energies. To have the double-power-law energy spectrum of electrons at the high energies, three empirical models are proposed in terms of the dependences of the spectral power index, the electron temperature, and the threshold energy on the electron energy. The numerical result obtained by this study for the energy spectrum of electrons at energies ~1-200 keV fits very well with the double-power-law spectrum measurement given by Reames, von Rosenvinge, & Lin. Title: Identifying High-Redshift Active Galactic Nuclei Using X-Ray Hardness Authors: Wang, J. X.; Malhotra, S.; Rhoads, J. E.; Norman, C. A. Bibcode: 2004ApJ...612L.109W Altcode: 2004astro.ph..5499W The X-ray color (hardness ratio) of optically undetected X-ray sources can be used to distinguish obscured active galactic nuclei (AGNs) at low and intermediate redshift from viable high-redshift (i.e., z>5) AGN candidates. This will help determine the space density, ionizing photon production, and X-ray background contribution of the earliest detectable AGNs. High-redshift AGNs should appear soft in X-rays, with hardness ratio HR~-0.5, even if there is strong absorption by a hydrogen column density NH up to 1023 cm-2, simply because the absorption redshifts out of the soft X-ray band in the observed frame. Here the X-ray hardness ratio is defined as HR=(H-S)/(H+S), where S and H are the soft and hard band net counts detected by Chandra. High-redshift AGNs that are Compton thick (NH>~1024 cm-2) could have HR~0.0 at z> 5. However, these should be rare in deep Chandra images, since they have to be >~10 times brighter intrinsically, which implies a >~100 times drop in their space density. Applying the hardness criterion (HR<0.0) can filter out about 50% of the candidate high-redshift AGNs selected from deep Chandra images. Title: X-Ray Nondetection of the Lyα Emitters at z~4.5 Authors: Wang, J. X.; Rhoads, J. E.; Malhotra, S.; Dawson, S.; Stern, D.; Dey, A.; Heckman, T. M.; Norman, C. A.; Spinrad, H. Bibcode: 2004ApJ...608L..21W Altcode: 2004astro.ph..4611W The Lyα emitters found at z~4.5 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lyα line, which can be produced by either narrow-lined active galactic nuclei (AGNs) or by stellar populations with a very high proportion of young, massive stars. To investigate the AGN scenario, we obtained two deep Chandra exposures to study the X-ray nature of the Lyα emitters. The 172 ks deep Chandra image on the LALA Boötes field was presented in a previous paper, and in this Letter we present a new Chandra deep exposure (174 ks) on the LALA Cetus field, which doubled our sample of X-ray-imaged Lyα sources and imaged the brightest source among our Lyα emitters. None of the 101 Lyα sources covered by two Chandra exposures were detected individually in X-rays, with a 3 σ limiting X-ray flux of F0.5-10.0keV<3.3×10-16 ergs cm-2 s-1 for on-axis targets. The sources remain undetectable in the stacked image, implying a 3 σ limit to the average luminosity of L2-8keV<2.8×1042 ergs s-1. The resulting X-ray to Lyα ratio is greater than 21 times lower than the ratios for known high-redshift type II quasars. Together with optical spectra obtained at Keck, we conclude that no evidence of AGN activity was found among our Lyα emitters at z~4.5. Title: Deep Chandra image in the Bootes Field Authors: Wang, J. X.; Malhotra, S.; Rhoads, J. E.; Brown, M. J. I.; Dey, A.; Jannuzi, B. T.; Dawson, S.; Spinrad, H.; Heckman, T. M.; Norman, C. A.; Stern, D.; Tiede, G. P.; Tozzi, P. Bibcode: 2004AAS...204.4814W Altcode: 2004BAAS...36..748W A 172 ks long Chandra exposure was carried out in the LALA-Bootes field and a similar one for the LALA cetus field. These exposure were deep enough to detect LALA sources, if they were type-II quasars. Lyman-alpha emitters found with LALA show high equivalent widths and AGN phenomenon is one explanation. A total of 101 Ly-alpha emitters are covered by the two Chandra images. No Ly-alpha emitters are detected individually or in the co-added X-ray images. Our analysis indicates that fewer than 4.8 Ly-alpha emitters could be possible AGNs based on the upper limit of their average X-ray to Ly-alpha ratio. The two X-ray images are among the deepest taken by Chandra, with a total of 348 X-ray sources detected, similar to the number of X-ray sources in Chandra Deep Field South. We also see field-to-field variations of the hard X-ray source counts in different Chandra fields, due to large scale structure. Title: Lyman Alpha Galaxies at High Redshift Authors: Rhoads, J. E.; Malhotra, S.; Dawson, S.; Dey, A.; Jannuzi, B. T.; Spinrad, H.; Stern, D.; Wang, J. X.; Xu, C.; Brown, M. J. I.; Landes, E. Bibcode: 2004AAS...204.4803R Altcode: 2004BAAS...36..746R Because strong Lyman alpha emission is expected from young star forming galaxies at high redshift, it offers an efficient tool for identifying these galaxies. The Large Area Lyman Alpha survey is one of the first and largest successful searches for Lyman alpha emitting galaxies at high redshift. In the LALA Bootes field (which lies within the NOAO Deep Wide-Field Survey's Bootes field) we have obtained deep narrowband images covering 1/3 square degree in each of eight filters, sampling redshifts z=4.5, 5.7, and 6.5. We focus here on the higher redshift windows, where we have confirmed a luminous Lyman alpha emitting galaxy at z=6.535 and several others in the z=5.7 window. We discuss the physical properties of these objects, including their contribution to star formation rates and metal production. We also discuss the implications of Lyman alpha galaxy observations at z=6.5 for reionization. Title: Identifying high redshift AGNs from X-ray colors Authors: Wang, J. X.; Rhoads, J. E.; Malhotra, S.; Norman, C. A. Bibcode: 2004AAS...204.4407W Altcode: 2004BAAS...36Q.732W The X-ray color (hardness ratio) can be used to select high redshift active galactic nuclei (AGNs) among the x-ray selected, optically blank candidates. High redshift AGNs should appear soft in X-ray with hardness ratio HR ∼ -0.5, even if there is strong absorption with NH up to 1023 cm-2, simply because the absorption redshifts out of the soft X-ray band in the observed frame. Here the X-ray hardness ratio is defined as HR= (H-S)/(H+S), where S and H are the soft and hard band net counts detected by Chandra. High redshift AGNs that are Compton thick (NH >= 1024 cm-2) could have HR ∼ 0.0, however, these should be rare in deep Chandra images, since they have to be ∼ 10 times brighter intrinsicly, which leads to ∼ 100 times drop in their space density. All known z > 4 AGNs show soft x-ray colors. Applying the hardness criterion (HR < 0.0) can filter out about 50% of the candidate high redshift AGNs selected from deep Chandra images. Title: Investigation for the cosmic ray ground level enhancements during solar cycle 23 Authors: Wang, R. G.; Wang, J. X. Bibcode: 2004cosp...35.2410W Altcode: 2004cosp.meet.2410W Major solar energetic particle (SEP) events associated with large solar flares can give rise to the cosmic ray ground level enhancements (GLEs). Up to December 2003 during solar activity cycle 23, 12 GLEs (Number from 55 to 66) have been recorded by the worldwide network of neutron monitors (NMs) in the 87 solar proton events (with peak flux exceeding 10 {(cm^2 sec ster)}-1 for more than 10 MeV solar protons ). Eeight of the 12 GLEs (67%) are originated from southern hemisphere and 10 of the 12 GLEs (83%) are originated from western hemisphere. Each GLE is corresponded by a solar coronal mass ejection (CME) which had the potential of producing disturbances to the geospace. Among the 12 relevant CMEs 8 large ones should be responsible for the 8 major geomagnetic storms (defined by disturbance storm time index ≤ -100 nT). The largest 3 geomagnetic storms (Dst≤ -300 nT) correspond to the 3 GLEs (No.59, No.65 and No.66) which have great proton flux with energy > 10 MeV. It seems to imply that the solar proton events having great proton flux are more likely to bring major geomagnetic storms. Furthermore, solar proton event with high flux is not a condition for creating GLE. Some proposal factors are discussed for GLE production. Title: The 172 ks Chandra Exposure of the LALA Bootes Field: X-Ray Source Catalog Authors: Wang, J. X.; Malhotra, S.; Rhoads, J. E.; Brown, M. J. I.; Dey, A.; Heckman, T. M.; Jannuzi, B. T.; Norman, C. A.; Tiede, G. P.; Tozzi, P. Bibcode: 2004AJ....127..213W Altcode: 2003astro.ph..9705W We present an analysis of a deep, 172 ks Chandra observation of the Large Area Lyman Alpha survey (LALA) Bootes field, obtained with the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This is one of the deepest Chandra images of the extragalactic sky; only the 2 Ms Chandra Deep Field North (CDF-N) and 1 Ms Chandra Deep Field South (CDF-S) are substantially deeper. In this paper we present the X-ray source catalog obtained from this image, along with an analysis of source counts and optical identifications. The X-ray image is composed of two individual observations obtained in 2002 and reaches 0.5-2.0 and 2.0-10.0 keV flux limits of 1.5×10-16 and 1.0×10-15 ergs cm-2 s-1, respectively, for point sources near the aim point. A total of 168 X-ray sources were detected: 160 in the 0.5-7.0 keV band, 132 in the 0.5-2.0 keV band, and 111 in the 2.0-7.0 keV band. The X-ray source counts were derived and compared with those from other Chandra deep surveys; the hard X-ray source density of the LALA Bootes field is 33% higher than that of CDF-S at the flux level of 2.0×10-15 ergs cm-2 s-1, confirming the field-to-field variances of the hard-band source counts reported by previous studies. The deep exposure resolves >~72% of the 2.0-10.0 keV X-ray background. Our primary optical data are R-band imaging from the NOAO Deep Wide-Field Survey (NDWFS), with a limiting magnitude of R=25.7 (Vega, 3 σ, and 4" diameter aperture). We have found optical counterparts for 152 of the 168 Chandra sources (90%); 144 of these are detected in the R-band image, and eight have optical counterparts in other bands (either BW, V, I, or z'). Among the R-band nondetected sources, not more than 11 of them can possibly be at z>5, based on the hardness ratios of their X-ray emission and nondetections in bluer bands (BW, V). The majority (~76%) of the X-ray sources are found to have log(fX/fR) within 0.0+/-1 these are believed to be AGNs. Most of the X-ray-faint/optically bright sources [log(fX/fR)<-1.0] are optically extended; these are low-z normal galaxies or low-luminosity AGNs. There is also a population of sources that are X-ray overluminous for their optical magnitudes [log(fX/fR)>1.0], which are harder in X-ray and are probably obscured AGNs. Title: Reconnection in the lower solar atmosphere and coronal mass ejections Authors: Wang, J. X. Bibcode: 2004cosp...35.3644W Altcode: 2004cosp.meet.3644W In 1985 a phenomenon in solar physics, named as magnetic flux cancellation, was first described in details by Livi, Wang, Martin (1995). Since then, it has been revealed that flux cancellation is intrinsically correlated to the most, if not all, types of solar activity, such as flare, filament formation and eruption in active regions, and ubiquitous small-scale activity, e.g., X-ray bright points, explosive events, mini-filament eruptions and so on. Only recently, it was discovered that flux cancellation appeared to be a very key magnetic evolution leading to the initiation of coronal mass ejections (Zhang et al. 2001; Zhang and Wang, 2001; Zhang, Wang, Nitta, 2001). On the other hand, the nature of flux cancellation has become a topic of persistent interests and debates. In this talk, we review the observational properties of magnetic flux cancellation and the relevant theoretical studies, and present observations of flux cancellation from vector magnetograph in CME associated source regions. Then, we demonstrate that at least some well-observed flux cancellation by vector magnetograph fits nicely the scenario of magnetic reconnection in the lower solar atmosphere, i.e., the partially ionized plasma. It is suggested that the magnetic reconnection in the lower solar atmosphere is the key elements in the CME magnetism. Title: Periodicities in solar coronal mass ejections Authors: Lou, Yu-Qing; Wang, Yu-Ming; Fan, Zuhui; Wang, Shui; Wang, Jing Xiu Bibcode: 2003MNRAS.345..809L Altcode: 2003astro.ph..7277L Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during the most recent solar maximum cycle 23 are reported here for the first time using the four-year data (1999 February 5 to 2003 February 10) of the Large Angle Spectrometric Coronagraph on board the Solar and Heliospheric Observatory. In parallel, mid-term quasi-periodicities in solar X-ray flares (class >M5.0) from the Geosynchronous Operational Environment Satellites and in daily averages of Ap index for geomagnetic disturbances from the World Data Center at the International Association for Geomagnetism and Aeronomy are also examined for the same four-year time-span. By Fourier power spectral analyses, the CME data appear to contain significant power peaks at periods of ~358 +/- 38, ~272 +/- 26, ~196 +/- 13 d and so forth, while, except for the ~259 +/- 24 d period, X-ray solar flares of class >~M5.0 show the familiar Rieger-type quasi-periods at ~157 +/- 11, ~122 +/- 5, ~98 +/- 3 d and shorter ones down to ~34 +/- 0.5 d. In the data of daily averages of Ap index, the two significant peaks at periods ~273 +/- 26 and ~187 +/- 12 d (the latter is most prominent) could imply that CMEs (periods at ~272 +/- 26 and ~196 +/- 13 d) may be proportionally correlated with quasi-periodic geomagnetic storm disturbances. At the speculative level, the ~138 +/- 6 d period might imply that X-ray flares of class >~M5.0 (period at ~157 +/- 11 d) drive certain types of geomagnetic disturbances; the ~28 +/- 0.2 d periodicity is most likely caused by recurrent high-speed solar winds at the Earth's magnetosphere. For the same three data sets, we further perform Morlet wavelet analysis to derive period-time contours and identify wavelet power peaks and time-scales at the 99 per cent confidence level for comparisons. Several conceptual aspects of possible equatorially trapped Rossby-type waves at and beneath the solar photosphere are discussed. Title: On the Latitudinal Distribution of Sunspot Groups over a Solar Cycle Authors: Li, K. J.; Wang, J. X.; Zhan, L. S.; Yun, H. S.; Liang, H. F.; Zhao, H. J.; Gu, X. M. Bibcode: 2003SoPh..215...99L Altcode: The latitudinal distribution of sunspot groups over a solar cycle is investigated. Although individual sunspot groups of a solar cycle emerge randomly at any middle and low latitude, the whole latitudinal distribution of sunspot groups of the cycle is not stochastic and, in fact, can be represented by a probability density function of the Γ distribution having maximum probability at about 15.5°. The maximum amplitude of a solar cycle is found to be positively correlated against the number of sunspot groups at high latitude (≥35°) over the cycle, as well as the mean latitude. Also, the relation between the asymmetry of sunspot groups and its latitude is investigated, and a pattern of the N-S asymmetry in solar activity is suggested. Title: A Fluid Dynamics Approach for the Computation of Nonlinear Force-Free Magnetic Field Authors: Li, Jing-Qun; Wang, Jing-Xiu; Wei, Feng-Si Bibcode: 2003ChJAA...3..247L Altcode: Inspired by the analogy between the magnetic field and velocity field of incompressible fluid flow, we propose a fluid dynamics approach for computing nonlinear force-free magnetic fields. This method has the advantage that the divergence-free condition is automatically satisfied, which is a sticky issue for many other algorithms, and we can take advantage of modern high resolution algorithms to process the force-free magnetic field. Several tests have been made based on the well-known analytic solution proposed by Low & Lou. The numerical results are in satisfactory agreement with the analytic ones. It is suggested that the newly proposed method is promising in extrapolating the active region or the whole sun magnetic fields in the solar atmosphere based on the observed vector magnetic field on the photosphere. Title: An Explanation for Large Enhancements of Nitrogen relative to Carbon and Oxygen in Solar 3He-rich Events Authors: Zhang, T. X.; Wang, J. X. Bibcode: 2003ApJ...588L..57Z Altcode: Preferential heating and abundance enhancements of carbon (C), nitrogen (N), and oxygen (O) in solar 3He-rich energetic particles are investigated in terms of the two-stage acceleration model proposed by Zhang. It is shown that C+5, N+6, and O+7 are preferentially heated by H-cyclotron waves with a frequency close to twice the 3He-cyclotron frequency through the third harmonic resonance. If the initial electron temperature of the solar corona is in the range of ~2-3.2 MK, the abundance of N in high-energy particles due to the second-stage acceleration is enhanced by a factor of ~4-12 relative to C and O. The abundance pattern of C, N, and O obtained from the two-stage acceleration model is consistent with recent measurements (Mason, Mazur, & Dwyer). In addition, harmonic resonances of neon, silicon, magnesium, sulfur, calcium, and iron with the H-cyclotron waves are discussed. Title: No X-Ray-bright Type II Quasars among the Lyα Emitters Authors: Malhotra, S.; Wang, J. X.; Rhoads, J. E.; Heckman, T. M.; Norman, C. A. Bibcode: 2003ApJ...585L..25M Altcode: 2003astro.ph..1622M The Lyα emitters found at z=4.5 and 5.7 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in the Lyα line. Such lines can be produced by narrow-lined active galactic nuclei or by stellar populations with a very high proportion of young massive stars. To check for type II (i.e., narrow-lined) quasars, we obtained a deep X-ray image of 49 Lyα sources in a single field of the ACIS instrument on the Chandra X-Ray Observatory. None of these sources was detected with a 3 σ limiting X-ray luminosity of 2.9×1043 ergs s-1. For comparison, the two known high-redshift type II quasars have luminosities of 4×1043 ergs s-1 before extinction correction. The sources remain undetected in stacked images of the 49 Lyα sources (with 6.5 Ms effective Chandra on-axis exposure) at 3 σ limits of 4.9×1042. The resulting X-ray-to-Lyα ratio is about 4-24 times lower than the ratio for known type II quasars, while the average Lyα luminosity of the LALA sample is between the two type II's. The cumulative X-ray-to-Lyα ratio limit is also below that of 90% of low-redshift Seyfert galaxies. Title: Influence of turbulent magnetic fields on mode frequencies Authors: Bi, S. L.; Liao, Y.; Wang, J. X. Bibcode: 2003A&A...397.1069B Altcode: To investigate the physical nature of solar convective zone, we employ the observed frequency shifts of solar oscillations to study the influence of magnetic perturbation inside the Sun on the low-l solar p-mode oscillations. We describe the various possibility of frequency shifts for a time-dependent source of MHD turbulence. For the magnetic perturbation contribution, we obtain the frequency shifts of modes with different degree as a function of the spectrum of fluctuating magnetic field. The frequency shift is found to increase with the strength of magnetic fields in solar interior, and its temporal behavior closely follows the phase of the synthetic solar activity cycle. Our analysis indicates that the magnetic activities cause shifts of up to 0.3 muHz . It is obviously shown that mode frequency, which is sensitive to the effect of magnetic fields, can be used as a diagnostic tool for the presence of turbulent magnetic fields in the convection zone. Title: Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in SNO Authors: McDonald, A. B.; Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bigu, J.; Biller, S. D.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Bühler, G.; Cameron, J.; Chan, Y. D.; Chen, H. H.; Chen, M.; Chen, X.; Cleveland, B. T.; Clifford, E. T. H.; Cowan, J. H. M.; Cowen, D. F.; Cox, G. A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Gagnon, N.; Germani, J. V.; Gil, S.; Graham, K.; Grant, D. R.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A. S.; Hamian, A. A.; Handler, W. B.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howe, M.; Hykawy, J. G.; Isaac, M. C. P.; Jagam, P.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P. T.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kouzes, R.; Kutter, T.; Kyba, C. C. M.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Locke, W.; Luoma, S.; Lyon, J.; Majerus, S.; Mak, H. B.; Maneira, J.; Manor, J.; Marino, A. D.; McCauley, N.; McDonald, D. S.; McFarlane, K.; McGregor, G.; Meijer Drees, R.; Mifflin, C.; Miller, G. G.; Milton, G.; Moffat, B. A.; Moorhead, M.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; O'Neill, M.; Okada, C. E.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Poon, A. W. P.; Radcliffe, T. J.; Roberge, A.; Robertson, B. C.; Robertson, R. G. H.; Rosendahl, S. S. E.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schaffer, K. K.; Schwendener, M. H.; Schülke, A.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W. E.; Spreitzer, T.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Stonehill, L. C.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P. M.; Trent, P. T.; Tserkovnyak, Y. I.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Waltham, C. E.; Wang, J. -X.; Wark, D. L.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters, J. M.; Yeh, M. Bibcode: 2002AIPC..646...43M Altcode: The Sudbury Neutrino Observatory (SNO) is a 1,000 tonne heavy water Cerenkov-based neutrino detector situated 2,000 meters underground in INCO's Creighton Mine near Sudbury, Ontario, Canada. For the neutrinos from 8B decay in the Sun SNO observes the Charged Current neutrino reaction sensitive only to electron neutrinos and others (Neutral Current and Elastic Scattering) sensitive to all active neutrino types and thereby can search for direct evidence of neutrino flavor change. Using these reactions and assuming the standard 8B shape, the ve component of the 8B solar flux is φe = 1.76- 0.05+0.05(stat.)- 0.09+0.09 (syst.) × 106 cm-2s-1 for a kinetic energy threshold of 5 MeV. The non-ve component is fgr μτ = 3.41- 0.45+0.45(stat.)- 0.45+0.48 (syst.) × 106 cm-2s-1, 5.3σ greater than zero, providing strong evidence for solar ve flavor transformation. The total flux measured with the NC reaction is fgr NC = 5.09- 0.43+0.44(stat.)- 0.43+0.46 (syst.) × 106 cm-2s-1, consistent with solar models. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0% +/- 6.3%-1.4+1.5% of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the ve asymmetry is found to be 7.0% +/- 4.9%-1.2+1.3%. A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the Large Mixing Angle (LMA) solution. Title: A statistical study on the geoeffectiveness of Earth-directed coronal mass ejections from March 1997 to December 2000 Authors: Wang, Y. M.; Ye, P. Z.; Wang, S.; Zhou, G. P.; Wang, J. X. Bibcode: 2002JGRA..107.1340W Altcode: We have identified 132 Earth-directed coronal mass ejections (CMEs) based on the observations of the Large Angle Spectroscopic Coronagraph (LASCO) and Extreme Ultraviolet Imaging Telescope (EIT) on board of Solar and Heliospheric Observatory (SOHO) from March 1997 to December 2000 and carried out a statistical study on their geoeffectiveness. The following results are obtained: (1) Only 45% of the total 132 Earth-directed halo CMEs caused geomagnetic storms with Kp ≥ 5; (2) The initial sites of these geoeffective halo CMEs are rather symmetrically distributed in the heliographic latitude of the visible solar disc, while asymmetrical in longitude with the majority located in the west side of the central meridian; (3) The frontside halo CMEs accompanied with solar flares (identified from GOES-8 satellite observations) seem to be more geoeffective; (4) Only a weak correlation between the CME projected speed and the transit time is revealed. However, for the severe geomagnetic storms (with Kp ≥ 7), a significant correlation at the confidence level of 99% is found. Title: A method for the prediction of relative sunspot number for the remainder of a progressing cycle with application to cycle 23 Authors: Li, K. J.; Zhan, L. S.; Wang, J. X.; Liu, X. H.; Yun, H. S.; Xiong, S. Y.; Liang, H. F.; Zhao, H. Z. Bibcode: 2002A&A...392..301L Altcode: In this paper, we investigate the prospect of using previously occurring sunspot cycle signatures to determine future behavior in an ongoing cycle, with specific application to cycle 23, the current sunspot cycle. We find that the gross level of solar activity (i.e., the sum of the total number of sunspots over the course of a sunspot cycle) associated with cycle 23, based on a comparison of its first several years of activity against similar periods of preceding cycles, is such that cycle 23 best compares to cycle 2. Compared to cycles 2 and 22, respectively, cycle 23 appears 1.08 times larger and 0.75 times as large. Because cycle 2 was of shorter period, we infer that cycle 23 also might be of shorter length (period less than 11 years), ending sometime in late 2006 or early 2007. Title: Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory Authors: Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bigu, J.; Biller, S. D.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Bühler, G.; Cameron, J.; Chan, Y. D.; Chen, H. H.; Chen, M.; Chen, X.; Cleveland, B. T.; Clifford, E. T.; Cowan, J. H.; Cowen, D. F.; Cox, G. A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Gagnon, N.; Germani, J. V.; Gil, S.; Graham, K.; Grant, D. R.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A. S.; Hamian, A. A.; Handler, W. B.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howe, M.; Hykawy, J. G.; Isaac, M. C.; Jagam, P.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P. T.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kouzes, R.; Kutter, T.; Kyba, C. C.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Locke, W.; Luoma, S.; Lyon, J.; Majerus, S.; Mak, H. B.; Maneira, J.; Manor, J.; Marino, A. D.; McCauley, N.; McDonald, A. B.; McDonald, D. S.; McFarlane, K.; McGregor, G.; Meijer Drees, R.; Mifflin, C.; Miller, G. G.; Milton, G.; Moffat, B. A.; Moorhead, M.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; O'Neill, M.; Okada, C. E.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Poon, A. W.; Radcliffe, T. J.; Roberge, A.; Robertson, B. C.; Robertson, R. G.; Rosendahl, S. S.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schaffer, K. K.; Schwendener, M. H.; Schülke, A.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W.; Spreitzer, T.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Stonehill, L. C.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P. M.; Trent, P. T.; Tserkovnyak, Y. I.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Waltham, C. E.; Wang, J. -X.; Wark, D. L.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters, J. M.; Yeh, M. Bibcode: 2002PhRvL..89a1301A Altcode: 2002nucl.ex...4008S; 2002nucl.ex...4008C Observations of neutral-current ν interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard 8B shape, the νe component of the 8B solar flux is φe = 1.76+0.05-0.05(stat)+0.09- 0.09(syst)×106 cm-2 s-1 for a kinetic energy threshold of 5 MeV. The non- νe component is φμτ = 3.41+0.45-0.45(stat)+0.48- 0.45(syst)×106 cm-2 s-1, 5.3σ greater than zero, providing strong evidence for solar νe flavor transformation. The total flux measured with the NC reaction is φNC = 5.09+0.44-0.43(stat)+0.46- 0.43(syst)×106 cm-2 s-1, consistent with solar models. Title: Measurement of Day and Night Neutrino Energy Spectra at SNO and Constraints on Neutrino Mixing Parameters Authors: Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bigu, J.; Biller, S. D.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Bühler, G.; Cameron, J.; Chan, Y. D.; Chen, H. H.; Chen, M.; Chen, X.; Cleveland, B. T.; Clifford, E. T.; Cowan, J. H.; Cowen, D. F.; Cox, G. A.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunford, M.; Dunmore, J. A.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Ford, R. J.; Formaggio, J. A.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Gagnon, N.; Germani, J. V.; Gil, S.; Graham, K.; Grant, D. R.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A. S.; Hamian, A. A.; Handler, W. B.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howe, M.; Hykawy, J. G.; Isaac, M. C.; Jagam, P.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Kazkaz, K.; Keener, P. T.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kouzes, R.; Kutter, T.; Kyba, C. C.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Locke, W.; Luoma, S.; Lyon, J.; Majerus, S.; Mak, H. B.; Maneira, J.; Manor, J.; Marino, A. D.; McCauley, N.; McDonald, A. B.; McDonald, D. S.; McFarlane, K.; McGregor, G.; Meijer Drees, R.; Mifflin, C.; Miller, G. G.; Milton, G.; Moffat, B. A.; Moorhead, M.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; O'Neill, M.; Okada, C. E.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Poon, A. W.; Radcliffe, T. J.; Roberge, A.; Robertson, B. C.; Robertson, R. G.; Rosendahl, S. S.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schaffer, K. K.; Schwendener, M. H.; Schülke, A.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sims, C. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W.; Spreitzer, T.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Stonehill, L. C.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P. M.; Trent, P. T.; Tserkovnyak, Y. I.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Waltham, C. E.; Wang, J. -X.; Wark, D. L.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J. R.; Wittich, P.; Wouters, J. M.; Yeh, M. Bibcode: 2002PhRvL..89a1302A Altcode: 2002nucl.ex...4009S; 2002nucl.ex...4009C The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%+1.5-1.4% of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the νe asymmetry is found to be 7.0%+/-4.9%+1.3-1.2%. A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution. Title: Magnetic Field Strengths and Structures from Radio Observations of Solar Active Regions Authors: Zhang, Chang-Xi; Gelfreikh, G. B.; Wang, Jing-Xiu Bibcode: 2002ChJAA...2..266Z Altcode: Radio observations of some active regions (ARs) obtained with the Nobeyama radioheliograph at λ=1.76 cm are used for estimating the magnetic field strength in the upper chromosphere, based on thermal bremsstrahlung. The results are compared with the magnetic field strength in the photosphere from observations with the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observing Station of Beijing Astronomical Observatory. The difference in the magnetic field strength between the two layers seems reasonable. The solar radio maps of active regions obtained with the Nobeyama radioheliograph, both in total intensity (I-map) and in circular polarizations (V-map), are compared with the optical magnetograms obtained with the SMFT. The comparison between the radio map in circular polarization and the longitudinal photospheric magnetogram of a plage region suggests that the radio map in circular polarization is a kind of magnetogram of the upper chromosphere. The comparison of the radio map in total intensity with the photospheric vector magnetogram of an AR shows that the radio map in total intensity gives indications of magnetic loops in the corona, thus we have a method of defining the coronal magnetic structure from the radio I-maps at λ=1.76 cm. Analysing the I-maps, we identified three components: (a) a compact bright source; (b) a narrow elongated structure connecting two main magnetic islands of opposite polarities (observed in both the optical and radio magnetograms); (c) a wide, diffuse, weak component that corresponds to a wide structure in the solar active region which shows in most cases an S or a reversed S contour, which is probably due to the differential rotation of the Sun. The last two components suggest coronal loops on different spatial scales above the neutral line of the longitudinal photospheric magnetic field. Title: Regularity of the north-south asymmetry of solar activity Authors: Li, K. J.; Wang, J. X.; Xiong, S. Y.; Liang, H. F.; Yun, H. S.; Gu, X. M. Bibcode: 2002A&A...383..648L Altcode: In the present work, the dominant hemisphere of solar activity in each of solar cycles 12 to 22 has been clarified by calculating the actual probability of the hemispheric distribution of several solar activity phenomena using long-term observational records. An attempt is made to demonstrate that a long characteristic time scale, about 12-cycle length, is inferred to occur in solar activity. Title: Can Asymmetry of Solar Activity be Extended into Extended Cycle? Authors: Li, Ke-Jun; Wang, Jing-Xiu; Liang, Hong-Fei; Gu, Xiao-Ma Bibcode: 2002ChJAA...2...66L Altcode: With the use of the Royal Greenwich Observatory data set of sunspot groups, an attempt is made to examine the north-south asymmetry of solar activity in the ``extended'' solar cycles. It is inferred that the asymmetry established for individual solar cycles does not extend to the "extended" cycles. Title: The Chandra Deep Field-South: The 1 Million Second Exposure Authors: Rosati, P.; Tozzi, P.; Giacconi, R.; Gilli, R.; Hasinger, G.; Kewley, L.; Mainieri, V.; Nonino, M.; Norman, C.; Szokoly, G.; Wang, J. X.; Zirm, A.; Bergeron, J.; Borgani, S.; Gilmozzi, R.; Grogin, N.; Koekemoer, A.; Schreier, E.; Zheng, W. Bibcode: 2002ApJ...566..667R Altcode: We present the main results from our 940 ks observation of the Chandra Deep Field-South using the source catalog described in an accompanying paper by Giacconi et al. We extend the measurement of source number counts to 5.5×10-17 ergs cm-2 s-1 in the soft 0.5-2 keV band and 4.5×10-16 ergs cm-2 s-1 in the hard 2-10 keV band. The hard-band logN-logS shows a significant flattening (slope ~=0.6) below ~10-14 ergs cm-2 s-1, leaving at most 10%-15% of the X-ray background to be resolved, the main uncertainty lying in the measurement of the total flux of the X-ray background (XRB). On the other hand, the analysis in the very hard 5-10 keV band reveals a relatively steep logN-logS (slope ~=1.3) down to 10-15 ergs cm-2 s-1. Together with the evidence of a progressive flattening of the average X-ray spectrum near the flux limit, this indicates that there is still a nonnegligible population of faint hard sources to be discovered at energies not well probed by Chandra, which possibly contributes to the 30 keV bump in the spectrum of the XRB. We use optical redshifts and identifications, obtained with the Very Large Telescope, for one-quarter of the sample to characterize the combined optical and X-ray properties of the Chandra Deep Field-South sample. Different source types are well separated in a parameter space that includes X-ray luminosity, hardness ratio, and R-K color. Type II objects, while redder on average than the field population, have colors that are consistent with being hosted by a range of galaxy types. Type II active galactic nuclei are mostly found at z<~1, in contrast with predictions based on active galactic nucleus population synthesis models, thus suggesting a revision of their evolutionary parameters. Based on observations made at the European Southern Observatory (ESO), the Paranal Observatory Office, Antofagasta, Chile. The ESO Imaging Survey observations have been carried out using the ESO New Technology Telescope (NTT) at the La Silla Observatory, Avenida, El Santo 1538, La Serena, Chile (ESO LP 164.O-O561). Title: What Can We Learn From Constructing CME Models Authors: Lin, J.; Wang, J. X. Bibcode: 2002stma.conf..137L Altcode: No abstract at ADS Title: Magnetic Flux Cancellation Associated with Coronal Mass Ejections Authors: Wang, J. X.; Zhang, J.; Deng, Y. Y. Bibcode: 2002stma.conf...93W Altcode: No abstract at ADS Title: New Results from the X-Ray and Optical Survey of the Chandra Deep Field-South: The 300 Kilosecond Exposure. II. Authors: Tozzi, P.; Rosati, P.; Nonino, M.; Bergeron, J.; Borgani, S.; Gilli, R.; Gilmozzi, R.; Hasinger, G.; Grogin, N.; Kewley, L.; Koekemoer, A.; Norman, C.; Schreier, E.; Szokoly, G.; Wang, J. X.; Zheng, W.; Zirm, A.; Giacconi, R. Bibcode: 2001ApJ...562...42T Altcode: 2001astro.ph..3014T We present results from 300 ks of X-ray observations of the Chandra Deep Field-South. The field of the four combined exposures is now 0.1035 deg2, and we reach a flux limit of 10-16 ergs s-1 cm-2 in the 0.5-2 keV soft band and 10-15 ergs s-1 cm-2 in the 2-10 keV hard band, i.e., a factor of 2 fainter than the previous 120 ks exposure. The total catalog is composed of 197 sources including 22 sources detected only in the hard band, 51 only in the soft band, and 124 detected in both bands. We now have the optical spectra for 86 optical counterparts. The logN-logS relationship of the whole sample confirms the flattening with respect to the ASCA hard counts and the ROSAT soft counts. The average logarithmic slopes of the number counts are α=0.66+/-0.06 and α=0.92+/-0.12 in the soft and hard bands, respectively. Double power-law fits to the differential counts show evidence of further flattening at the very faint end to slopes of 0.5+/-0.1 and 0.6+/-0.2 in the soft and hard bands, respectively. We compute the total contribution to the X-ray background (XRB) in the 2-10 keV band, which now amounts to (1.45+/-0.15)×10-11 ergs cm-2 s-1 deg-2 (after the inclusion of the ASCA sources to account for the bright end) to a lower flux limit of 10-15 ergs s-1 cm-2. This corresponds to 60%-90% of the unresolved hard XRB, given the uncertainties on its actual value. We confirm previous findings on the average spectrum of the sources, which is well described by a power law with Γ=1.44+/-0.03, and the progressive hardening of the sources at lower fluxes. In particular, we find that the average spectral slope of the sources is flatter than the average for fluxes lower than 9×10-15 ergs s-1 cm-2 in the hard band. The hardening of the spectra is consistent with an increasing fraction of absorbed objects (NH>1022 cm-2) at low fluxes. From 86 redshifts available at present, we find that hard sources have on average lower redshifts (z<=1) than soft sources. Their typical luminosities and optical spectra show that most of these sources are obscured active galactic nuclei (AGNs), as expected by AGN population synthesis models of the XRB. We are still in the process of finding hard sources that constitute the remaining fraction of the total XRB. Most of the sources detected only in the soft band appear to be optically normal galaxies with luminosities LX~=1040-1042 ergs s-1. This population appears to be a mix of normal galaxies, possibly with enhanced star formation, and galaxies with low-level nuclear activity. Based on observations performed at the European Southern Observatory, Paranal, Chile. Title: Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the Quasar PG 1351+64 Authors: Zheng, W.; Kriss, G. A.; Wang, J. X.; Brotherton, M.; Oegerle, W. R.; Blair, W. P.; Davidsen, A. F.; Green, R. F.; Hutchings, J. B.; Kaiser, M. E. Bibcode: 2001ApJ...562..152Z Altcode: 2001astro.ph..7536Z We present a moderate-resolution (~20 km s-1) spectrum of the mini-broad absorption line quasar (QSO) PG 1351+64 between 915 and 1180 Å, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional low-resolution spectra at longer wavelengths were also obtained with the Hubble Space Telescope (HST) and ground-based telescopes. Broad absorption is present on the blue wings of C III λ977, Lyβ, O VI λλ1032, 1038, Lyα, N V λλ1238, 1242, Si IV λλ1393, 1402, and C IV λλ1548, 1550. The absorption profile can be fitted with five components at velocities of ~-780, -1049, -1629, -1833, and -3054 km s-1 with respect to the emission-line redshift of z=0.088. All the absorption components cover a large fraction of the continuum source, as well as the broad-line region. The O VI emission feature is very weak, and the O VI/Lyα flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The UV continuum shows a significant change in slope near 1050 Å in the rest frame. The steeper continuum shortward of the Lyman limit extrapolates well to the observed weak X-ray flux level. The absorbers' properties are similar to those of high-redshift broad absorption line QSOs. The derived total column density of the UV absorbers is on the order of 1021 cm-2, unlikely to produce significant opacity above 1 keV in the X-ray. Unless there is a separate, high-ionization X-ray absorber, the QSO's weak X-ray flux may be intrinsic. The ionization level of the absorbing components is comparable to that anticipated in the broad-line region; therefore, the absorbers may be related to broad-line clouds along the line of sight. Based on observations made for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission, operated by the Johns Hopkins University under NASA contract NAS 5-32985, and observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities of Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: The Chandra Deep Field South: the 1 Million Second Authors: Rosati, P.; Tozzi, P.; Giacconi, R.; Gilli, R.; Hasinger, G.; Kewley, L.; Mainieri, V.; Nonino, M.; Norman, C.; Szokoly, G.; Wang, J. X.; Zirm, A.; Bergeron, J.; Borgani, S.; Gilmozzi, R.; Grogin, N.; Koekemoer, A.; Schreier, E.; Zheng, W. Bibcode: 2001astro.ph.10452R Altcode: We present the main results from our 940 ksec observation of the Chandra Deep Field South (CDFS), using the source catalog described in an accompanying paper (Giacconi et al. 2001). We extend the measurement of source number counts to 5.5e-17 erg/cm^2/s in the soft 0.5-2 keV band and 4.5e-16 erg/cm^2/s in the hard 2-10 keV band. The hard band LogN-LogS shows a significant flattening (slope~=0.6) below ~1e-14 erg/cm^2/s, leaving at most 10-15% of the X-ray background (XRB) to be resolved, the main uncertainty lying in the measurement of the total flux of the XRB. On the other hand, the analysis in the very hard 5-10 keV band reveals a relatively steep LogN-LogS (slope ~=1.3) down to 1e-15 erg/cm^2/s. Together with the evidence of a progressive flattening of the average X-ray spectrum near the flux limit, this indicates that there is still a non negligible population of faint hard sources to be discovered at energies not well probed by Chandra, which possibly contribute to the 30 keV bump in the spectrum of the XRB. We use optical redshifts and identifications, obtained with the VLT, for one quarter of the sample to characterize the combined optical and X-ray properties of the CDFS sample. Different source types are well separated in a parameter space which includes X-ray luminosity, hardness ratio and R-K color. Type II objects, while redder on average than the field population, have colors which are consistent with being hosted by a range of galaxy types. Type II AGN are mostly found at z<~1, in contrast with predictions based on AGN population synthesis models, thus suggesting a revision of their evolutionary parameters. Title: Measurement of the Rate of νe + d --> p + p + e- Interactions Produced by 8B Solar Neutrinos at the Sudbury Neutrino Observatory Authors: Ahmad, Q. R.; Allen, R. C.; Andersen, T. C.; Anglin, J. D.; Bühler, G.; Barton, J. C.; Beier, E. W.; Bercovitch, M.; Bigu, J.; Biller, S.; Black, R. A.; Blevis, I.; Boardman, R. J.; Boger, J.; Bonvin, E.; Boulay, M. G.; Bowler, M. G.; Bowles, T. J.; Brice, S. J.; Browne, M. C.; Bullard, T. V.; Burritt, T. H.; Cameron, K.; Cameron, J.; Chan, Y. D.; Chen, M.; Chen, H. H.; Chen, X.; Chon, M. C.; Cleveland, B. T.; Clifford, E. T.; Cowan, J. H.; Cowen, D. F.; Cox, G. A.; Dai, Y.; Dai, X.; Dalnoki-Veress, F.; Davidson, W. F.; Doe, P. J.; Doucas, G.; Dragowsky, M. R.; Duba, C. A.; Duncan, F. A.; Dunmore, J.; Earle, E. D.; Elliott, S. R.; Evans, H. C.; Ewan, G. T.; Farine, J.; Fergani, H.; Ferraris, A. P.; Ford, R. J.; Fowler, M. M.; Frame, K.; Frank, E. D.; Frati, W.; Germani, J. V.; Gil, S.; Goldschmidt, A.; Grant, D. R.; Hahn, R. L.; Hallin, A. L.; Hallman, E. D.; Hamer, A.; Hamian, A. A.; Haq, R. U.; Hargrove, C. K.; Harvey, P. J.; Hazama, R.; Heaton, R.; Heeger, K. M.; Heintzelman, W. J.; Heise, J.; Helmer, R. L.; Hepburn, J. D.; Heron, H.; Hewett, J.; Hime, A.; Howe, M.; Hykawy, J. G.; Isaac, M. C.; Jagam, P.; Jelley, N. A.; Jillings, C.; Jonkmans, G.; Karn, J.; Keener, P. T.; Kirch, K.; Klein, J. R.; Knox, A. B.; Komar, R. J.; Kouzes, R.; Kutter, T.; Kyba, C. C.; Law, J.; Lawson, I. T.; Lay, M.; Lee, H. W.; Lesko, K. T.; Leslie, J. R.; Levine, I.; Locke, W.; Lowry, M. M.; Luoma, S.; Lyon, J.; Majerus, S.; Mak, H. B.; Marino, A. D.; McCauley, N.; McDonald, A. B.; McDonald, D. S.; McFarlane, K.; McGregor, G.; McLatchie, W.; Drees, R. Meijer; Mes, H.; Mifflin, C.; Miller, G. G.; Milton, G.; Moffat, B. A.; Moorhead, M.; Nally, C. W.; Neubauer, M. S.; Newcomer, F. M.; Ng, H. S.; Noble, A. J.; Norman, E. B.; Novikov, V. M.; O'Neill, M.; Okada, C. E.; Ollerhead, R. W.; Omori, M.; Orrell, J. L.; Oser, S. M.; Poon, A. W.; Radcliffe, T. J.; Roberge, A.; Robertson, B. C.; Robertson, R. G.; Rowley, J. K.; Rusu, V. L.; Saettler, E.; Schaffer, K. K.; Schuelke, A.; Schwendener, M. H.; Seifert, H.; Shatkay, M.; Simpson, J. J.; Sinclair, D.; Skensved, P.; Smith, A. R.; Smith, M. W.; Starinsky, N.; Steiger, T. D.; Stokstad, R. G.; Storey, R. S.; Sur, B.; Tafirout, R.; Tagg, N.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Thornewell, P.; Trent, P. T.; Tserkovnyak, Y. I.; van Berg, R.; van de Water, R. G.; Virtue, C. J.; Waltham, C. E.; Wang, J. -X.; Wark, D. L.; West, N.; Wilhelmy, J. B.; Wilkerson, J. F.; Wilson, J.; Wittich, P.; Wouters, J. M.; Yeh, M. Bibcode: 2001PhRvL..87g1301A Altcode: 2001nucl.ex...6015S; 2001nucl.ex...6015C Solar neutrinos from 8B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of νe's is measured by the CC reaction rate to be φCC(νe) = 1.75+/-0.07(stat)+0.12- 0.11(syst)+/-0.05(theor)×106 cm-2 s-1. Comparison of φCC(νe) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3σ difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- νe component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99×106 cm-2 s-1. Title: Resolving the X-ray background with Chandra: the 1 MS observation of the Chandra Deep Field South * Authors: Tozzi, P.; Bergeron, J.; Borgani, S.; Giacconi, R.; Gilli, R.; Gilmozzi, R.; Grogin, N.; Hasinger, G.; Kellerman, K.; Kewley, L.; Koekemoer, A.; Mainier, V.; Nonino, M.; Norman, C.; Rosati, P.; Schreier, E.; Shaver, P.; Szokoly, G.; Wang, J. X.; Zheng, W.; Zirm, A. Bibcode: 2001cghr.confE..66T Altcode: No abstract at ADS Title: The Chandra Deep Field South Authors: Giacconi, R.; Rosati, P.; Tozzi, P.; Borgani, S.; Hasinger, G.; Bergeron, J.; Gilmozzi, R.; Nonino, M.; Gilli, R.; Zirm, A.; Wang, J. X.; Zheng, W.; Kellermann, K. I.; Shaver, P.; Schreier, E.; Koekemoer, A.; Grogin, N.; Norman, C. Bibcode: 2000AAS...197.9001G Altcode: 2000BAAS...32.1562G We present results from the on-going ultra deep Chandra observations in the Chandra Deep Field South (CDF-S). As of October 2000, we have collected an exposure of 300 ksec which covers an area of 0.1 deg2. These new data confirm and strengthen some of the conclusions of our initial analysis based on 130ksec observations (Giacconi et al. 2000). At the current depth, the source surface density is 3000/deg2. Number counts in the hard band (2-10keV) have overtaken the soft (0.5-2) counts and show evidence of flattening below 10-15 erg/cm2/s [2-10 keV]. The hardening of the source spectra continues to fainter fluxes, most likely the result of an increasing absorption column. We discuss the implications of these observations in light of new population synthesis models. We will also show the spectro-photometric and morphological properties of the optical counterparts from the on-going source identification program with the VLT and HST/WFPC2. We acknowledge support from NASA grants NAG-8-1527 and NAG-8-1133. Title: The X-Ray Absorber in Broad Absorption Line Quasars Authors: Wang, T. G.; Brinkmann, W.; Yuan, W.; Wang, J. X.; Zhou, Y. Y. Bibcode: 2000ApJ...545...77W Altcode: 2000astro.ph..8291W Recent observations of Broad Absorption Line (BAL) quasars demonstrated that the soft X-ray emission of these objects is extremely weak, and convincing evidence for very strong absorption by a high column density (~1023.5 cm-2) was obtained for PG 1411+442, even though it is one of the few BAL QSOs strongly detected in soft X-rays. This paper examines the ionization status and geometry of the X-ray absorber by combining the properties of the UV lines with the X-ray continuum absorption. We show that the gas has to have large column densities in ions of major UV absorption lines, such as C IV, N V, O VI, and Ne VIII, in order to have sufficient opacity around 0.2-0.35 keV. The UV absorption lines have to be saturated if the X-ray absorber intersects the line of sight to the UV continuum emission region. A uniformly covering UV and X-ray absorption model can be constructed for PG 1411+442, but in some other soft X-ray-detected BAL QSOs, such as PG 1001+054, the observed line optical depth is much lower than expected from the X-ray-absorbing material. We propose a scheme in which a substantial fraction of the line of sight to the continuum source may be covered by either an optically thick flow or clouds in a narrow velocity range, but in which the total covering factor of either the whole flow or all clouds is close to unity. The absorber can contribute significantly to the extremely highly ionized emission lines, such as O VI λλ1032/1037 and Ne VIII λλ770/780, if it covers a substantial fraction of solid angle and if the density is higher than 108 cm-3. However, it has very little impact on the medium- and low-ionization UV lines such as N V and C IV. The profiles of Ne VIII and O VI lines may be indicators for the kinematics of the X-ray absorber in QSOs. The observed Ne VIII line profiles in QSOs suggest that the velocity of the gas projected onto our line of sight is similar to that seen in the outflows of the UV BALs. Title: The Sudbury Neutrino Observatory Authors: Boger, J.; Hahn, R. L.; Rowley, J. K.; Carter, A. L.; Hollebone, B.; Kessler, D.; Blevis, I.; Dalnoki-Veress, F.; DeKok, A.; Farine, J.; Grant, D. R.; Hargrove, C. K.; Laberge, G.; Levine, I.; McFarlane, K.; Mes, H.; Noble, A. T.; Novikov, V. M.; O'Neill, M.; Shatkay, M.; Shewchuk, C.; Sinclair, D.; Clifford, E. T. H.; Deal, R.; Earle, E. D.; Gaudette, E.; Milton, G.; Sur, B.; Bigu, J.; Cowan, J. H. M.; Cluff, D. L.; Hallman, E. D.; Haq, R. U.; Hewett, J.; Hykawy, J. G.; Jonkmans, G.; Michaud, R.; Roberge, A.; Roberts, J.; Saettler, E.; Schwendener, M. H.; Seifert, H.; Sweezey, D.; Tafirout, R.; Virtue, C. J.; Beck, D. N.; Chan, Y. D.; Chen, X.; Dragowsky, M. R.; Dycus, F. W.; Gonzalez, J.; Isaac, M. C. P.; Kajiyama, Y.; Koehler, G. W.; Lesko, K. T.; Moebus, M. C.; Norman, E. B.; Okada, C. E.; Poon, A. W. P.; Purgalis, P.; Schuelke, A.; Smith, A. R.; Stokstad, R. G.; Turner, S.; Zlimen, I.; Anaya, J. M.; Bowles, T. J.; Brice, S. J.; Esch, E. -I.; Fowler, M. M.; Goldschmidt, A.; Hime, A.; McGirt, A. F.; Miller, G. G.; Teasdale, W. A.; Wilhelmy, J. B.; Wouters, J. M.; Anglin, J. D.; Bercovitch, M.; Davidson, W. F.; Storey, R. S.; Biller, S.; Black, R. A.; Boardman, R. J.; Bowler, M. G.; Cameron, J.; Cleveland, B.; Ferraris, A. P.; Doucas, G.; Heron, H.; Howard, C.; Jelley, N. A.; Knox, A. B.; Lay, M.; Locke, W.; Lyon, J.; Majerus, S.; Moorhead, M.; Omori, M.; Tanner, N. W.; Taplin, R. K.; Thorman, M.; Wark, D. L.; West, N.; Barton, J. C.; Trent, P. T.; Kouzes, R.; Lowry, M. M.; Bell, A. L.; Bonvin, E.; Boulay, M.; Dayon, M.; Duncan, F.; Erhardt, L. S.; Evans, H. C.; Ewan, G. T.; Ford, R.; Hallin, A.; Hamer, A.; Hart, P. M.; Harvey, P. J.; Haslip, D.; Hearns, C. A. W.; Heaton, R.; Hepburn, J. D.; Jillings, C. J.; Korpach, E. P.; Lee, H. W.; Leslie, J. R.; Liu, M. -Q.; Mak, H. B.; McDonald, A. B.; MacArthur, J. D.; McLatchie, W.; Moffat, B. A.; Noel, S.; Radcliffe, T. J.; Robertson, B. C.; Skensved, P.; Stevenson, R. L.; Zhu, X.; Gil, S.; Heise, J.; Helmer, R. L.; Komar, R. J.; Nally, C. W.; Ng, H. S.; Waltham, C. E.; Allen, R. C.; Bühler, G.; Chen, H. H.; Aardsma, G.; Andersen, T.; Cameron, K.; Chon, M. C.; Hanson, R. H.; Jagam, P.; Karn, J.; Law, J.; Ollerhead, R. W.; Simpson, J. J.; Tagg, N.; Wang, J. -X.; Alexander, C.; Beier, E. W.; Cook, J. C.; Cowen, D. F.; Frank, E. D.; Frati, W.; Keener, P. T.; Klein, J. R.; Mayers, G.; McDonald, D. S.; Neubauer, M. S.; Newcomer, F. M.; Pearce, R. J.; de Water, R. G. V.; Berg, R. V.; Wittich, P.; Ahmad, Q. R.; Beck, J. M.; Browne, M. C.; Burritt, T. H.; Doe, P. J.; Duba, C. A.; Elliott, S. R.; Franklin, J. E.; Germani, J. V.; Green, P.; Hamian, A. A.; Heeger, K. M.; Howe, M.; Drees, R. M.; Myers, A.; Robertson, R. G. H.; Smith, M. W. E.; Steiger, T. D.; Wechel, T. V.; Wilkerson, J. F. Bibcode: 2000NIMPA.449..172B Altcode: 1999nucl.ex..10016C; 1999nucl.ex..10016T The Sudbury Neutrino Observatory is a second-generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible. Title: X-Ray and Ultraviolet Spectral Properties of the X-Ray Transient Quasar PG 0844+349 Authors: Wang, T. G.; Brinkmann, W.; Matsuoka, M.; Wang, J. X.; Yuan, W. Bibcode: 2000ApJ...533..113W Altcode: Despite the fact that quasars are generally strong X-ray emitters, ROSAT discovered several objects with only very weak X-ray emission. In this paper, the X-ray data from ASCA and ROSAT and the UV spectra from Hubble Space Telescope (HST) and IUE of one of these quasars, PG 0844+349, are analyzed. The ROSAT spectrum can be well fitted by a single power law with Galactic absorption. No spectral variations were observed during changes of the 0.1-2.4 keV X-ray flux by a factor of 10 between the ROSAT All-Sky Survey and pointed observations, separated by 6 months. The ASCA satellite found the object in a high state with a photon index of 1.98 and an Fe Kα line with EW~300 eV. The X-ray flux in the 2-10 keV band is highly variable; the fastest variation detected is 60% in less than 2×104 s. The measured excess variance fits well the excess variance versus L2-10keV relation for Seyfert 1 galaxies; the flux variability in the 0.5-2.0 keV band shows a slightly higher amplitude than in the 2-10 keV band. We show that the optical microvariability of this object can actually be driven by reprocessing of the variable X-ray flux if one-half of the absorbed X-rays are reradiated in the optical-to-UV band. A weak broad intrinsic absorption line (FWHM~=800 km s-1), most likely Lyα absorption blueshifted by a velocity ~=-6000 km s-1 relative to the quasar's rest frame, is found in the HST Faint Object Spectrograph spectrum. A similar C IV broad absorption line may also be present in the low-resolution IUE spectrum. Historic light curves in the X-ray, UV, and optical bands indicate that the variability amplitude in the UV and optical bands is much smaller than in the X-ray band. The QSO can be classified as X-ray weak only on one occasion out of five X-ray observations. An analysis of the long-term behavior of several other X-ray-weak objects shows no indications of a similar large X-ray variability. Title: Ionized ultraviolet and soft X-ray absorption in the low-redshift active galactic nucleus PG 1126-041 Authors: Wang, T. G.; Brinkmann, W.; Wamsteker, W.; Yuan, W.; Wang, J. X. Bibcode: 1999MNRAS.307..821W Altcode: 1999astro.ph..3428W We present here the analysis of ultraviolet spectra from IUE and an X-ray spectrum from ROSAT PSPC observations of the X-ray-weak, far-infrared-loud AGN, PG 1126-041 (Mrk 1298). The first UV spectra taken in 1992 June, simultaneously with ROSAT, show strong absorption lines of Nv, Civ and Siiv, extending over a velocity range from -1000 to -5000kms^-1 with respect to the corresponding line centre. Our analysis shows that the broad emission-line region (BELR) is, at least partially, covered by the material causing these absorption lines. In the IUE spectrum taken in 1995 January, the continuum was a factor of 2 brighter and the UV absorption lines are found to be considerably weaker than in 1992, but little variation in the emission-line fluxes is found. With UV spectral indices of alpha_UV~=1.82 and 1.46 for the 1992 and 1995 data, the far-UV spectrum is steep. Based on the emission-line ratios and the broad-band spectral energy distribution, we argue that the steepness of the UV spectrum is unlikely to be caused by reddening. The soft X-ray emission in the ROSAT band is weak. A simple power-law model yields a very poor fit with a UV-to-X-ray spectral index alpha_UVX=2.3. Highly ionized (warm) absorption is suggested by the ROSAT data. After correcting for a warm absorber, the optical to X-ray spectral slope is close to the average of alpha_UVX~=1.67 for radio-quiet quasars. From photoionization calculations we find the following results. (1) A single-zone absorption model cannot explain simultaneously the UV absorption lines and the ionized X-ray absorption if metal abundances are solar. Furthermore, in order to be consistent with the equivalent width of the observed Lyalpha absorption line, the turbulent velocity of the warm absorber must be less than 190kms^-1, which imposes serious constraints on a disc wind model. (2) The UV absorption lines and their variability cannot be explained by a single-zone model with solar abundances and the large variability in the absorption lines suggests that Civ and Nv absorption lines are not severely saturated. (3) The absorption of the ionizing continuum by warm material strongly affects the emission-line spectrum. Title: How Saturated Are Absorption Lines in the Broad Absorption Line Quasar PG 1411+442? Authors: Wang, T. G.; Wang, J. X.; Brinkmann, W.; Matsuoka, M. Bibcode: 1999ApJ...519L..35W Altcode: 1999astro.ph..5054W Recently, convincing evidence was found for extremely large X-ray absorption by column densities greater than 1023 cm-2 in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. A detection of the unabsorbed soft X-ray and absorbed hard X-ray component will allow us to determine the total column density as well as the effective covering factor of the absorbing material, which are difficult to obtain from the UV absorption lines. Brinkmann et al. recently showed that both the unabsorbed and absorbed components are detected in the nearby very bright broad absorption line quasar PG 1411+442. In this Letter, we make a further analysis of the broadband X-ray spectrum and the UV spectrum from the Hubble Space Telescope and demonstrate that broad absorption lines are completely saturated at the bottom of absorption troughs. Title: Rapidly Variable Fe Kα Line in NGC 4051 Authors: Wang, J. X.; Zhou, Y. Y.; Xu, H. G.; Wang, T. G. Bibcode: 1999ApJ...516L..65W Altcode: 1999astro.ph..4321W We present a detailed analysis on the variability of the Fe K emission line in NGC 4051 using ASCA data. Through simple Gaussian line fits, we find not only obvious Fe K line variability with no significant difference in the X-ray continuum flux between two ASCA observations that were separated by ~ 440 days, but also rapid variability of the Fe K line on timescales ~104 s within the second observation. During the second observation, the line is strong (EW=733+206-219 eV) and broad (σ=0.96+0.49-0.35 keV) when the source is brightest and becomes weaker (EW=165+87-86 eV) and narrower (σ<0.09 keV) while the source is weakest. The equivalent width of the Fe K line correlates positively with the continuum flux, which shows an opposite trend with another Seyfert type 1 galaxy, MCG -6-30-15. Title: Solar sympathetic flares in two adjacent active regions Authors: Shi, Zhong-Xian; Wang, Jing-Xiu; Luan, Di Bibcode: 1997AcASn..38..257S Altcode: We describe the magnetic configurations of a group of two-ribbon flares in NOAA 6233 and their temporally correlated one-ribbon flares in NOAA 6240, and also the topological connectivity between the two active regions. The analyses show that the three one-ribbon flares took place in a unipolar flux region of positive polarity, which seems to be connected through a set of high-lying magnetic loops with the strong delta-sunspot, where the corresponding two-ribbon flares appeared. The interaction between the high-lying magnetic loops and the low-lying sheared magnetic loops in the delta-sunspot appears to be the primary cause for the two-ribbon flares. The accelerated electrons in the primary energy release may propagate along the high-lying magnetic loops (or the relevant separatrices), and result in the one-ribbon flares in NOAA 6240. Therefore, we suggest that these one-ribbon flares are the sympathetic flares of the correlated two-ribbon flares in NOAA 6233. Title: Evolution of Magnetic Helicity in Magnetic Reconnection Authors: Hu, Y. Q.; Xia, L. D.; Li, X.; Wang, J. X.; Ai, G. X. Bibcode: 1997SoPh..170..283H Altcode: This paper presents a definition of magnetic helicity specifically for two-dimensional magnetic fields and derives the associated helicity equation. The newly defined helicity is closely related to its three-dimensional counterpart and serves as a measure of the shear of magnetic field. Based on this, a numerical simulation is carried out on magnetic reconnection occurring in the lower solar atmosphere. It is found that the helicity dissipation due to magnetic reconnection is very small. A large amount of helicity is transferred upward and escapes from the domain of the solution, and the total helicity is approximately conserved during the magnetic reconnection and helicity transfer. This is in support of the applicability of a postulate, which was proposed by Taylor (1974, 1986) concerning the approximate conservation of magnetic helicity in the presence of resistive dissipation and magnetic reconnection in a highly conductive laboratory plasma, to the solar atmosphere. Title: Book Review: Proceedings of the third China-Japan seminar on solar physics / International Academic Publishers, Beijing, 1995 Authors: Wang, J. X.; Ai, G. X.; Sakurai, T.; Hirayama, T. Bibcode: 1996SoPh..169..225W Altcode: No abstract at ADS Title: Flares and velocity pattern around separatrix. Authors: Shi, Zhong-xian; Wang, Jing-xiu Bibcode: 1996ChA&A..20..305S Altcode: A close relationship between flares and magnetic flux cancellation at the photospheric layer has been observationally established in a number of active regions. The flux cancellation precedes the flares by a few hours up to a day. During this time a specific pattern appears in the radial velocity field in the chromosphere, namely, the magnetic separatrix appears as a narrow blue-shifted band while the flares all occur in the red-shifted regions on either side. This observation supports the identification of flux cancellation with magnetic reconnection in the lower atmosphere and confirms that the reconnection is closely related to fast energy release in the corona. Title: Magnetic Energy Buildup in a Quadrupole Field by Photospheric Shear Motion Authors: Hu, Y. Q.; Wang, J. X.; Ai, G. X.; Nie, Y. P. Bibcode: 1995SoPh..159..251H Altcode: Using a two-dimensional, dissipative magnetohydrodynamic model, this paper presents a numerical simulation of the magnetic energy buildup in a quadrupolar field by photospheric shear motion. When electric current density is larger than a certain critical value, an anomalous resistivity is introduced in order to account for the dissipation caused by instabilities in high current regions. It is shown that like a bipolar field, a quadrupolar field can efficiently store magnetic free energy through photospheric shear motion. Electric current formed by shear concentrates on the separatrix and magnetic loops rooted in areas where the shear velocity gradient is large. The atmosphere is heated by anomalous resistive dissipation during the shear. Both magnetic and thermal energy increases nonlinearly with shearing displacement. When the anomalous resistivity increases or the critical current density decreases, the growth rate reduces for magnetic energy but goes up for thermal energy. Title: On the transport of magnetic energy and complexity to the solar corona Authors: Wang, Jing-xiu Bibcode: 1995ChA&A..19..480W Altcode: For the active corona—a system consisting of electromagnetic fields and particles, the only open field surface is the solar photosphere. Interaction between the velocity and magnetic fields on the photosphere is the primary cause of the upward transport of magnetic energy and complexity to the corona, with the diffusion process there also playing a role. Title: Flares and separatrices between magnetic loops Authors: Shi, Zhong-xian; Wang, Jing-xiu; Wang, Hai-min Bibcode: 1995ChA&A..19..469S Altcode: Time sequences of vector magnetograms of Hauirou and Big Bear Solar Observatories have provided us the opportunity to identify the individual magnetic loops and athe separatrices between them. Based on the continuous observatin of vector magnetic field of NOAA 7469 from 4 to 12 April 1993, for the first time, the authors have identified the magnetic loop systems and relevant separatrices for such an active region. The observational signature ofthe cross-section of separatrices on the photosphere is as follows: (1) High degree of magnetic shear at or close to the separatrices;

(2) Steep gradient of line-of-sight magnetic field (∼ 0.1 G/km) crossing the neutral line.

(3) Flux cancellation from both sides of the separatrices. At this point the transverse field partly changes its alignment.

During the observed period, flare activity took place repeatedly in the vicinity of the separatrices. Title: Preflare State Authors: Rust, David M.; Sakurai, Takashi; Gaizauskas, Victor; Hofmann, Axel; Martin, Sara F.; Priest, Eric R.; Wang, Jing-Xiu Bibcode: 1994SoPh..153....1R Altcode: Discussion on the preflare state held at the Ottawa Flares 22 Workshop focused on the interpretation of solar magnetograms and of Hα filament activity. Magnetograms from several observatories provided evidence of significant build up of electric currents in flaring regions. Images of X-ray emitting structures provided a clear example of magnetic relaxation in the course of a flare. Emerging and cancelling magnetic fields appear to be important for triggering flares and for the formation of filaments, which are associated with eruptive flares. Filaments may become unstable by the build up of electric current helicity. Examples of heliform eruptive filaments were presented at the Workshop. Theoretical models linking filaments and flares are briefly reviewed. Title: A method for resolving the 180-degree ambiguity in the observed transverse field direction Authors: Wang, Jing-Xiu Bibcode: 1994ChA&A..18Q.355W Altcode: No abstract at ADS Title: A preliminary treatment of data from the full-disk magnetograph Authors: Liu, Yang; Song, Guo-feng; Wang, Jing-shan; Wang, Jing-xiu Bibcode: 1994ChA&A..18..319L Altcode: A full-disk magnetogram obtained with the full-disk magnetograph of Huairou Solar Observing Station shows similar morphological features and magnetic field intensities as in traditional small scale magnetograms obtained by the solar magnetic field telescope at the same site. Title: An Alternative Method for Removing the 180DEG Ambiguity of the Observed Transverse Field Direction Authors: Wang, J. X. Bibcode: 1994AcApS..14..166W Altcode: No abstract at ADS Title: A Study of Data Obtained by Full Disk Magnetograph Authors: Liu, Y.; Song, G. F.; Wang, J. S.; Wang, J. X. Bibcode: 1994AcApS..14..191L Altcode: No abstract at ADS Title: Shear Angle of Vector Magnetic Field Authors: Lu, Y. P.; Wang, J. X.; Wang, H. N. Bibcode: 1993AcApS..13..291L Altcode: No abstract at ADS Title: A New Method of Calculating the Vertical Current in Solar Active Regions Authors: Wang, J. X. Bibcode: 1993AcASn..34..436W Altcode: 1993AcASn..34..438W No abstract at ADS Title: An instance of the localized chromospheric polarity reversal Authors: Wang, Jing-Xiu; Shi, Zhong-Xian Bibcode: 1992ChA&A..16..325W Altcode: At the chromospheric level, a localized magnetic feature with polarity opposite to the underlying photospheric magnetic field has been observed in a rapidly formed sunspot. The strength of this reversed polarity is several hundred gauss. Seven subflares, centering around the reversed polarity, have been identified in observation of nine hours. The flares showed progressive increase in size and extent with the develop- ment of the reversed polarity. The bipolar feature above the unipolar magnetic flux can only mean that a bundle of magnetic lines of force has been kinked or knotted, or a self-closed flux system has been developed above the photosphere. Title: Lorentzian contributions to x-ray lineshapes in Si(Li) spectroscopy Authors: Campbell, J. L.; Wang, J. -X. Bibcode: 1992XRS....21..223C Altcode: No abstract at ADS Title: The relation between the twisting motion of a quiescent filament and the magnetic field Authors: Shi, Zhong-Xian; Wang, Jing-Xiu Bibcode: 1992ChA&A..16..350S Altcode: The twisting motion of a quiescent filament in AR5572 was observed on 8 July 1989. Based on the time sequence of magnetograms, Hβ fitergrams and Hβ Dopplergrams obtained at Huairou Solar Observing Station of Beijing Astronomical Observatory, the twisting motion of the filament is identified to be related to three cancelling magnetic features in the filament channel. Title: Osmium-Iridium Correlation and Osmium Isotopic Composition in Some Geological Boundaries and Meteorites Authors: Liu, Y. Z.; Wang, J. X.; Mao, X. Y.; Chai, C. F. Bibcode: 1992Metic..27Q.251L Altcode: Since the pioneering study of Alvarez et al. on K/T boundary event, Ir has long been considered to be the main indicator of extraterrestrial materials in boundaries, while little work about Os and its isotopic composition have been done. In this work a sophisticated radiochemical separation procedure together with neutron activation analsis (NAA) method was established for the determination of Os in some geological boundaries (P epsilon/epsilon, K/T, D/C, O/S, P/T). Combined with our early work--determination of Ir abundances [1], the sources of boundary events were deciphered by using the Os/Ir ratios. Simultaneously ^184Os/^190Os ratios in K/T boundaries, as well as inclusions of Allende chondrite and acid-insoluble residues of iron meteorites (Nandan, Jianshi, Longchang) were determined to search for the Os isotopic composition anomalies resulted from the extrasolar components by RNAA. The results show that the Os abundances exhibit a positive correlation with the Ir abundances for overall K/T boundary samples, but only the Os/Ir ratios of K/T boundaries, with the average of 0.98 +- 0.55, are in excellent agreement with 1.01 of the solar system [2], Accordingly, it provides new evidence for an extraterrestrial source of the K/T event. The results of ^184Os/^190Os ratios, with uncertainties of less than 1%, indicate there is no remarkable ^184Os/^190Os ratio anomaly in the K/T boundary samples, which implies the impacting matter may be from the solar system not the extrasolar, while no anomaly exists in the inclusions of Allende chondrite and acid-insoluble residues of iron meteorites, which disagree with the results obtained by Goel [3]. REFERENCES [1] Chai Chifang (1988) Isotopenpraxis 24, pp. 257-272. [2] Anders E. and Grevesse N. (l989) Geochim. Cosmochim. Acta 53, 197-214. [3] Goel P.S.(1987) Proc. Indian Acad. Sci. (Earth Planet. Sci), 96, pp. 81-102. Title: An approach to the development of magnetic shear Authors: Wang, Jing-xiu Bibcode: 1992ChA&A..16..207W Altcode: In view of an approximate description of magnetic shear by non-potential character of a force-free magnetic field, the force-free factor α would be a measure of magnetic shear, and the shear development would be analytically described by a differential equation dα/dt= 1/β 2∇· G+ V·∇α, where, G = ∂B/∂t × B, might be called as the generation function of magnetic shear. It is clearly shown by this equation that the magnetic shear is generated by local dynamo action resulting from the interaction between magnetic field and plasma motion. It is also illustrated that the squeezing and pressing of opposite polarity fields, the flux emergence and submergence would be as effective as shear motion in producing magnetic shear. Title: Direct indication of magnetic reconnection in solar photosphere Authors: Wang, Jing-Xiu; Shi, Zhong-Xian Bibcode: 1992AcApS..11..389W Altcode: A direct indication of magnetic reconnection in solar photosphere has been found for the first time with the aid of the time sequence of vector magnetograms. The reconnection takes place in the interface between one pole of an emerging flux region and the old flux of opposite polarity. It occurs well after a subflare with X-ray classification of C2.9 when flux cancellation in the interface had lasted for several hours. It is suggested that the reconnection in the photosphere would be a common phenomenon on the sun. Title: An example of localized chromospheric polarity reversal Authors: Wang, Jing-Xiu; Shi, Zhong-Xian Bibcode: 1992AcASn..33...95W Altcode: In the chromosphere, a localized magnetic feature with polarity opposite to the underlying photospheric magnetic field is observed above a fast formed sunspot. The strength of this reversal polarity is as strong as several hundred gauss. Centering around the reversal polarity, seven subflares are observed during nine hours before and after the reversal. Each flare shows progressively increasing size and spatial extent with the development of the reversal polarity. The reversal polarity above the photosphere can only mean that the magnetic lines of force have been kinked, twisted or knotted, or a close flux system has been formed above the photosphere. This newly observed phenomenon has not yet been possible to predict by either the current sunspot models or flare models. Title: Direct indication of magnetic reconnection in solar photosphere Authors: Wang, Jing-xiu; Shi, Zhong-xian Bibcode: 1992ChA&A..16...71W Altcode: A direct indication of magnetic reconnection in solar photosphere has been found for the first time with the aid of the time sequence of vector magnetograms. The reconnection takes place in the interface between one pole of an emerging flux region and the old flux of opposite polarity. It occurs well after a subflare with X-ray classification of C2.9 when flux cancellation in the interface had lasted for several hours. It is suggested that the reconnection in the photosphere would be a common phenomenon on the sun. Title: The Relation Between the Twisting Motion of a Quiescent Filament and the Magnetic Field Authors: Shi, Z. X.; Wang, J. X. Bibcode: 1992AcApS..12..196S Altcode: No abstract at ADS Title: Search for Celestial Gamma-Ray Point Sources with the Tibet Air Shower Array Authors: Amenomori, M.; Bai, Z. W.; Cao, Z.; Ding, L. K.; Hibino, K.; Hotta, N.; Huang, Q.; Huo, A. X.; Jia, H. G.; Jiang, G. Z.; Jiao, S. Q.; Kajino, F.; Kasahara, K.; Labaciren; Mei, D. M.; Meng, L.; Mimaciren; Mizutani, K.; Mu, J.; Nanjo, H.; Nishizawa, M.; Nusang; Ohnishi, M.; Ohta, I.; Ren, J. R.; Saito, T.; Sakata, M.; Shi, Z. Z.; Shibata, M.; Shirai, T.; Sun, X. X.; Sugimoto, H.; Tai, A.; Taira, K.; Tan, Y. H.; Tateyama, N.; Torii, S.; Wang, H.; Wang, J. X.; Wen, C. Z.; Yamamoto, Y.; Yang, H. M.; Yu, G. C.; Yuan, P.; Yuda, T.; Zeng, J. G.; Zhao, C. H.; Zhang, C. S.; Zhang, H. M.; Zhang, L.; Zhasang; Zhou, W. D. Bibcode: 1991ICRC....1..444A Altcode: 1991ICRC...22a.444A No abstract at ADS Title: Improved model for the intensity of low-energy tailing in Si(Li) x-ray spectra Authors: Campbell, J. L.; Wang, J. -X. Bibcode: 1991XRS....20..191C Altcode: No abstract at ADS Title: Two-dimensional power spectrum of small-scale magnetic fields on the quiet Sun Authors: Wang, Jing-xiu; Shi, Zhong-xian; Liu, Jian-qiang Bibcode: 1991ChA&A..15..239W Altcode: No abstract at ADS Title: Status and performance of the AS array of the Tibet ASγ experiment. Authors: Tibet As Gamma Collaboration; Amenomori, M.; Bai, Z. W.; Cao, Z.; Ding, L. K.; Feng, Z. Y.; Hibino, K.; Hotta, N.; Huang, Q.; Huo, A. X.; Jia, H. Y.; Jiang, G. Z.; Jiao, S. Q.; Kajino, F.; Kasahara, K.; Labaciren; Mei, D. M.; Meng, L.; Mimaciren; Mizutani, K.; Mu, J.; Nanjo, H.; Nishizawa, M.; Nusang; Ohnishi, M.; Ohta, I.; Ren, J. R.; Saito, T.; Sakata, M.; Shi, Z. Z.; Shibata, M.; Shirai, T.; Sun, X. X.; Sugimoto, H.; Tai, A.; Taira, K.; Tan, Y. H.; Tateyama, N.; Torii, S.; Wang, H.; Wang, J. X.; Wen, C. Z.; Yamamoto, Y.; Yang, H. M.; Yu, G. C.; Yuan, P.; Yuda, T.; Zeng, J. G.; Zhao, C. H.; Zhang, C. S.; Zhang, H. M.; Zhang, L.; Zhang, M.; Zhasang; Zhaxiciren; Zhou, W. D. Bibcode: 1991AIPC..220..257T Altcode: The Tibet ASγ experiment, which has started since January, 1990, is located at an altitude of 4300 m at Yangbaging in Tibet, China (90.5°E, 30.1°N). The air-shower array is composed of 49 scintillation counters for fast timing, each counter having an area of 0.5 m2, in a grid pattern with a spacing of 15 m and 16 density detectors. The analysis of experimental data shows that the performance of array is realized as expected by the Monte Carlo simulation. The detection threshold energy for γ-rays is ≡40 TeV; the peak energy 20 TeV. The angular resolution around 100 TeV is ≡0.5°. The systematic error of arrival direction is considerably smaller than the angular resolution in the concerned energy region. Title: Performance of the AS array in Tibet for search for gamma-ray point sources. Authors: Amenomori, M.; Bai, Z. W.; Cao, Z.; Ding, L. K.; Feng, Z. Y.; Hibino, K.; Hotta, N.; Huang, Q.; Huo, A. X.; Jia, H. Y.; Jiang, G. Z.; Jiao, S. Q.; Kajino, F.; Kasahara, K.; Labaciren; Mei, D. M.; Meng, L.; Mimaciren; Mizutani, K.; Mu, J.; Nanjo, H.; Nishizawa, M.; Nusang; Ohnishi, M.; Ohta, I.; Ren, J. R.; Saito, T.; Sakata, M.; Shi, Z. Z.; Shibata, M.; Shirai, T.; Sun, X. X.; Sugimoto, H.; Tai, A.; Taira, K.; Tan, Y. H.; Tateyama, N.; Torii, S.; Wang, H.; Wang, J. X.; Wen, C. Z.; Yamamoto, Y.; Yang, H. M.; Yu, G. C.; Yuan, P.; Yuda, T.; Zeng, J. G.; Zhao, C. H.; Zhang, C. S.; Zhang, H. M.; Zhang, L.; Zhang, M.; Zhasang; Zhaxiciren; Zhou, W. D. Bibcode: 1991aame.confQ.449A Altcode: No abstract at ADS Title: Direct Evidence of Magnetic Reconnection in Photospheric Layer on the Sun Authors: Wang, J. X.; Shi, Z. X. Bibcode: 1991AcApS..11..389W Altcode: No abstract at ADS Title: Search for gamma-ray point sources by the fast-timing detector array in Tibet. Authors: Amenomori, M.; Bai, Z. W.; Cao, Z.; Ding, L. K.; Feng, Z. Y.; Hibino, K.; Hotta, N.; Huang, Q.; Huo, A. X.; Jia, H. Y.; Jiang, G. Z.; Jiao, S. Q.; Kajino, F.; Kasahara, K.; Labaciren; Mei, D. M.; Meng, L.; Mimaciren; Mizutani, K.; Mu, J.; Nanjo, H.; Nishizawa, M.; Nusang; Ohnishi, M.; Ohta, I.; Ren, J. R.; Saito, T.; Sakata, M.; Shi, Z. Z.; Shibata, M.; Shirai, T.; Sun, X. X.; Sugimoto, H.; Tai, A.; Taira, K.; Tan, Y. H.; Tateyama, N.; Torii, S.; Wang, H.; Wang, J. X.; Wen, C. Z.; Yamamoto, Y.; Yang, H. M.; Yu, G. C.; Yuan, P.; Yuda, T.; Zeng, J. G.; Zhao, C. H.; Zhang, C. S.; Zhang, H. M.; Zhang, L.; Zhang, M.; Zhasang; Zhaxiciren; Zhou, W. D. Bibcode: 1991aame.confR.449A Altcode: As the first result of the Tibet experiment the data obtained during the week centered at the radio-burst from Cygnus X-3 on 15th of August, 1990, were analysed. But the preliminary results do not give any excess from Cygnus X-3 in this period at the median energy 30 TeV. Title: Fast appearances and disappearances of weak intranetwork magnetic fields Authors: Shi, Zhong-xian; Wang, Jing-xiu; Liu, Jian-qiang; Han, Feng; Liu, Gui-lin Bibcode: 1990ChA&A..14..325S Altcode: Under good seeing conditions (<2'), the high resolution magnetic field observation at Huairou Solar Observing Station'is capable of detecting the intranetwork field. An analysis of some magnetograms of 1988 September 5 shows: 1. That the observed weak intranetwork magnetic fields (WINF) with maximum flux B between 5 and 10 G are real structures. 2. That About 70% of the WINF became undetectable at ± 5 G level after 3.4 min and about 30% can be seen again. 3. That the number of WINF seen decreased exponentially with time, from which we estimated an upper limit of about 3 min for the mean life of a WINF. 4. That a WINF is a collection of unresolved flux elements, with a flux between 2.0(+16) and 1.0(+18) mx. Our results are similar to those in the magnetograms of 1984 September 9 obtained by the Big Bear Solar Observatory. Title: Two-dimensional power spectrum of small-scale magnetic fields on the quiet sun. Authors: Wang, Jing-Xiu; Shi, Zhong-Xian; Liu, Jian-Qiang Bibcode: 1990ChA&A..14..240W Altcode: 1990ChA&A..14..240. No abstract at ADS Title: Fast appearances and disappearances of weak intranetwork magnetic fields Authors: Shi, Zhong-Xian; Wang, Jing-Xiu; Liu, Jian-Qiang; Han, Feng; Liu, Gui-Lin Bibcode: 1990AcASn..31...63S Altcode: Results are presented of the analysis of magnetograms obtained, under conditions of best visibility, at the Huairou Station of the Beijing Observatory on September 5, 1988. The magnetograms showed the existence of weak intranetwork magnetic fields (INFs) which were appearing and disappearing, with a maximum flux B between 5 and 10 G. Evidence is presented that the weak appearing and disappearing INFs are real structures; about 70 percent of INFs become undetectable at the level of about 5 G after 3.4 min of observation; about 30 percent of INFs can be seen again. The number of weak INFs decreases exponentially with time, leading to an upper limit of about 3 min for the mean life of a weak INF. It is suggested that a weak INF is a collection of unresolved flux elements, with a flux between 2.0(+16) and 1.0(+18) Mx. Title: Two-dimensional power spectrum of small-scale magnetic fields on the quiet sun. Authors: Wang, Jing-Xiu; Shi, Zhong-Xian; Liu, Jian-Qiang Bibcode: 1990AcApS..10...96W Altcode: Based on magnetograms of September 5, 1988, the authors constructed a 2-D power spectrum for small-scale magnetic fields in a solar quiet region. The preliminary results are summarized as follows. (1) The solar magnetic fields in quiet regions are not only concentrated in discrete flux patches, but also distributed over discrete spatial periods. (2) The most obvious periods of small-scale fields are of supergranule scales. There are some peaks in the power spectrum corresponding to the spatial periods in mesogranule scales, and to the scales in between meso- and supergranules. Title: The observed size, flux spectrum of small-scale magnetic features. Authors: Wang, Jing-Xiu; Shi, Zhong-Xian; Liu, Jian-Qiang; Feng, Han; Liu, Gui-Lin Bibcode: 1989PBeiO..14...44W Altcode: The observed size, flux spectrum, and spatial distribution of small-scale magnetic features on the quiet photosphere are obtained statistically based on the high sensitivity magnetograms acquired at Huairou Solar Observing Station of Beijing Astronomical Observatory. The implications of these observational results are briefly discussed. Title: The relationship between solar flare and magnetic field in AR 5229. Authors: Shi, Zhong-Xian; Wang, Jing-Xiu; Liu, Gui-Lin; Hang, Feng Bibcode: 1989PYunO...1S..87S Altcode: Active region 5229 was studied during 13 - 18 November 1988 using Hβ filtergrams and Fe I 5324 videomagnetograms acquired at Huairou Solar Observing Station of Beijing Astronomical Observatory. Newly emerging flux, magnetic shear and magnetic flux cancellation were examined according to the evolution of magnetic fields. Preliminary results of the analysis were summarized. Title: An example of general solar-terrestrial effects of major solar events. Authors: Gao, Mei-Qing; Liu, Chun-Jie; Wang, Jing-Xiu Bibcode: 1989PYunO...1S.180G Altcode: The general solar-terrestrial effects including 20 parameters of major solar events in February, 1986 are analyzed and illustrated in terms of time sequence of various disturbances in interplanetary space, ionosphere and geomagnetic field. The characteristics of geomagnetic storm recorded at 6 stations are compared. The satellite anomaly and communication disturbance are also shown. Title: The Relationship Between Solar Flare and Magnetic Field in AR5229 Authors: Shi, Z. X.; Wang, J. X.; Liu, G. L.; Hang, F. Bibcode: 1989PYunO..87....1S Altcode: No abstract at ADS Title: Interpolated Dirac-Fock Values of L-Subshell X-Ray Emission Rates Including Overlap and Exchange Effects Authors: Campbell, J. L.; Wang, J. -X. Bibcode: 1989ADNDT..43..281C Altcode: Published theoretical L x-ray emission rates based upon a fixed atomic potential cover the atomic number range Z = 4 to 94. However, the presumably more accurate calculations employing different initial- and final-state potentials have been done for only 21 values of Z. The ratio of these two rates for each electric dipole transition as a function of Z is fitted using polynomials in piece-wise fashion. The fixed-potential emission rates are then renormalized by these interpolated ratios to provide equivalent two-potential rates. The errors incurred are generally under 0.2%. Title: A Example of General Solar-Terrestrial Effects of Major Solar Events Authors: Gao, M. Q.; Liu, C. J.; Wang, J. X. Bibcode: 1989PYunO.180....1G Altcode: No abstract at ADS Title: The fine structure and evolution of a subflare. Authors: Shi, Z. -X.; Chen, J.; Wang, J. -X. Bibcode: 1988ChJSS...8....1S Altcode: No abstract at ADS Title: Samples from Martian Craters: Origin of the Martian Soil by Hydrothermal Alteration of Impact Melt Deposits and Atmospheric Interactions with Ejecta During Crater Formation Authors: Wang, Jing-Xiu; Shi, Zhong-Xian Bibcode: 1988AcASn..29...48W Altcode: On July 9, 1984, continuous magnetograms with 1-2 arcsec spatial resolution, 2.5 min time resolution, and noise level below 5 Gauss were obtained. Analysis of these magnetograms after calibration and empirical corrections shows that, in addition to the transient, mixed polarity field described by Livingston and Harvey (1975), there is a stable type of unipolar flux form. These features have a typical size of 2-5 arcsecs in one dimension, a total flux of (+18) Mx, a field strength of approximately 40 G and a lifetime of several hours. The features are called intranetwork flux concentrations (INFC). Title: Intra-network flux concentrations Authors: Wang, Jing-xiu; Shi, Zhong-xian Bibcode: 1988ChA&A..12..241W Altcode: On 1984 July 9, we obtained continuous magnetograms with 1"-2" spatial resolution, 2.5min time resolution and noise level below 5 Gauss at Big Bear Solar Observatory. Analysis of' these magnetograms after calibration and empirical corrections shows that, in addition to the transient, mixed polarity field described by Livingston and Harvey (1975), there is a stable type of uni-polar flux forms. These features have a typical size of 2"-5" in one dimension, a total flux of (+18) Mx, a field strength of approximately 40G and a lifetime of several hours. We call these Intra-Network Flux Concentrations (INFC). Title: The Structure and Evolution of Smallscale Magnetic Fields on the Solar Surface Authors: Wang, J. X.; Shi, Z. X. Bibcode: 1988PrA.....6..105W Altcode: No abstract at ADS Title: The structure and evolution of small-scale magnetic fields on the solar surface. Authors: Wang, J. -X.; Shi, Z. -X. Bibcode: 1988PABei...6...94W Altcode: Small-scale magnetic fields on the solar surface, a term applied to all magnetic features and structures outside active regions, are usually much smaller in area than a supergranule. Currently they are divided into three categories: network magnetic fields, intranetwork magnetic fields and ephemeral active regions (or ephemeral regions). They are the majority of solar magnetic flux at any phase of solar cycle. Their appearance, disappearance and evolution may play an important role in heating the upper atmosphere. The observations of flux emergence, cancellation, coalescence and fragmentation cause us to view the network magnetic fields in a new way that the network fields are not only the products of the remnant fields of decaying active regions, but also the products of the remnant flux of ephemeral regions and intranetwork fields. Title: Evolution of network magnetic fields of solar quiet regions Authors: Shi, Zhong-xian; Wang, Jing-xiu Bibcode: 1987ChA&A..11..221S Altcode: There are 4 types of evolution patterns of network magnetic fields: (1) flux cancellation, the mutual disappearance of encountering fluxes of opposite polarity, (2) flux increase by emergence of ephemeral regions, (3) flux decrease of one polarity and (4) flux increase of one polarity, without emergence of ephemeral regions. From a time sequence of magnetograms of a quiet region of 1983 October 14, the evolution of 300 network features was measured. The magnetograms have a spatial resolution of 2 to 3 arcsec and a time resolution of about 2 hr. The statistics show that the contribution to flux decrease by Type 3 is 1.28 times that by Type 1, and the contribution to flux increase by Type 4 is 7 times that by Type 2. Title: Evolution of network magnetic fields of solar quiet regions Authors: Shi, Zhong-Xian; Wang, Jing-Xiu Bibcode: 1987AcASn..28..111S Altcode: The evolution of 300 quiet-region network features is followed in a time series of longitudinal magnetograms obtained (with spatial resolution 2-3 arcsec and time resolution about 2 h) using the VMG at Big Bear Solar Observatory on October 10-14, 1983. The results are presented in sample magnetograms and tables of numerical data. Four general evolution patterns are identified: (1) flux cancellation, (2) flux increase associated with the emergence of ephemeral regions, (3) one-polarity flux decrease, and (4) flux increase in one polarity without emergence of ephemeral regions. Patterns (3) and (4) are shown to be the dominant forms of decrease and increase, respectively. Title: A comparison between hard X-ray, soft X-ray, and microwave images and H-alpha isophote map of the 1980 november 5 flare Authors: Shi, Zhong-xian; Wang, Jing-xiu Bibcode: 1987ChA&A..11..162S Altcode: Filtergrams of the 1B/M1-M4 Hα flare of 1980 November 5 were digitized and the resulting isophote map compared with the hard X-, soft X, and microwave images. It was found: 1) During the first maximum. the high energy electrons did not penetrate the chromosphere. The Hα flare was probably caused by heat conduction from the (+7)-(+8) K hot plasma which generated the hard and soft X emissions. 2) The second maximum can be inferred to have been caused by bremsstrahlung of high energy electrons. The Hα maximum lagged behind the X-ray burst by not more than 5 seconds. 3) During the flash phase the area and the intensity of Hα emission increased in step with each other. 4) From the changes in the transverse magnetic field as outlined by Hα fibrils, (+31) ergs of magnetic energy is estimated to have been released in this flare. Title: Fine structure and evolution of a subflare. Authors: Shi, Z. -X.; Chen, J.; Wang, J. -X. Bibcode: 1987PBeiO..10...69S Altcode: No abstract at ADS Title: The Evolution of Network Magnetic Fields of the Solar Quiet Regions Authors: Shi, Z. X.; Wang, J. X. Bibcode: 1987AcApS..28..119S Altcode: No abstract at ADS Title: The meteorites of Boxian and its minerals. Authors: Wang, K. -R.; Wang, J. -X.; Li, X. -M. Bibcode: 1987KexT...32..545W Altcode: No abstract at ADS Title: Do moving magnetic features represent sunspot decay? Authors: Wang, J. -X.; Martin, S. F.; Livi, S. H. B. Bibcode: 1987PBeiO..10...58W Altcode: No abstract at ADS Title: A comparison between hard X-ray, soft X-ray, microwave burst images and Hα isophote map of the flare on November 5, 1980. Authors: Shi, Z. -X.; Wang, J. -X. Bibcode: 1987ChJSS...7...18S Altcode: No abstract at ADS Title: On the propagation of magneto-acoustic-gravity waves Authors: Wang, Jing-xiu Bibcode: 1986ChA&A..10..291W Altcode: An analysis of magneto-acoustic-gravity waves in the case of an isothermal atmosphere permeated by a uniform magnetic field is presented. The general solution is expressed in terms of generalized hypergeometric functions. It can be used in numerical simulation of oscillations in a magnetic atmosphere. It is shown that the elliptically polarized magneto-acoustic-gravity waves consist of a pair of surface waves and a pair of body waves above the cut-off frequency. The body waves along the magnetic field are similar to acoustic waves in an atmosphere and their cut-off frequency is unaffected by magnetic field. The transverse oscillation decreases with height. For the usual boundary condition, the longitudinal oscillation decreases with height; however, in some cases, it may contain terms that increase with height. The solution is singular on a family of ellipses in the frequency - horizontal wave number plane. Near these ellipses, the wave components grow indefinitely. Title: On the propagation of magneto-acoustic-gravity waves Authors: Wang, Jing-Xiu Bibcode: 1986AcApS...6..231W Altcode: An analysis of magnetoacoustic-gravity waves in the case of an isothermal atmosphere permeated by a uniform magnetic field is presented. The general solution is expressed in terms of generalized hypergeometric functions. It can be used in numerical simulation of oscillations in a magnetic atmosphere. It is shown that the elliptically polarized magnetoacoustic-gravity wave consist of a pair of surface waves and a pair of body waves above the cut-off frequency. The body waves along the magnetic field are similar to acoustic waves in an atmosphere, and their cut-off frequency is unaffected by magnetic field. The transverse oscillation decreases with height. For the usual boundary condition, the longitudinal oscillation decreases with height; however, in some cases, it may contain terms that increase with height. The solution is singular on a family of ellipses in the frequency - horizontal wave number plane. Near these ellipses, the wave components grow indefinitely. Title: The Hα characteristics of hard X-ray bursts. Authors: Shi, Zhong-Xian; Wang, Jing-Xiu Bibcode: 1986ChJSS...6..243S Altcode: The following results are obtained from the examination of 50 H-alpha flares. All flares with HXRBS are detectable from the emission of H-alpha + or - 2 A. They have at least two H-alpha kernels located in the opposite polarity regions. The H-alpha brightenings start earlier than HXRBS, while the H-alpha peaks, which correspond to the spikes of HXRBS very well, come later than that of HXRBS by several seconds. If the count rates of HXRBS are more than 1000, the kernels of H-alpha +2 A cover the penumbra; if the count rates are less than 200, the kernels do not cover the penumbra. Title: The boundary value problem of the solar force-free magnetic field with constant α and its analytical solution Authors: Chen, Z. -C.; Wang, J. -X. Bibcode: 1986SoPh..103..317C Altcode: In this paper we present a physical model which uses boundary conditions which seem to correspond more appropriately to actual situations. A boundary value problem of solar force-free magnetic field with constant α has been specified to represent the discretely concentrated characteristics of the longitudinal magnetic field on the photosphere. A unique analytical solution for the problem is obtained by a more strict method in mathematical physics. The most distinctive feature of our method is to make the solution be the superposition of the fields of single sources which are described by the physical parameters of corresponding sunspots on the photosphere, such as their position, strength, decay rates and the extent of the same polarity. The solution enables us to make an analytical description of the configuration of the magnetic field in the chromosphere and corona, and to investigate more conveniently its development as the foot points on the photosphere evolve. Title: A unique solution for the boundary value problem of the solar force free magnetic field with constant α. Authors: Chen, Z. -C.; Wang, J. -X. Bibcode: 1985KexT...30..768C Altcode: No abstract at ADS Title: The oscillator strength of hydrogen lines Authors: Shi, Zhong-xian; Wang, Jing-xiu Bibcode: 1984ChA&A...8...94S Altcode: We give a formal expression for the dependence of hydrogen line oscillator strength on departure from LTE and propose a method for determining this departure in the various sub-levels of the hydrogen atom in solar prominences. Results for 10 solar prominences are given. Finally, we discuss the possible implications of a smaller population in the 2p level than in the 2s level. Title: A method of analysing the emission lines of solar prominences Authors: Wang, Jing-xiu; Shi, Zhong-xian Bibcode: 1983ChA&A...7..269W Altcode: A new method of analysing the emission spectrum of solar prominences is presented, in which the source function is allowed to vary with optical depth. Least-squares fitting of the observed profile determines simultaneously the optical depth τ 0, the Doppler width Δλ D and the factor α characterising the variation of the source function. This method is applied to the early Balmer lines in ten prominences of Ref. [1]. The results show that the source function of the self-reversed H α line increases towards the centre of the prominence, the value at the centre is 1.2-2.5 times the value at the edge. Neglect of this variation will give too large values of τ 0. The degree of attenuation by selfabsorption also depends on this variation. Discussion of the variation gives support to the view that the main exciting mechanism in solar prominences is the scattering of the incident radiation. Title: A method of analyzing the emission lines of solar prominences Authors: Wang, J. -X.; Shi, Z. -X. Bibcode: 1983AcApS...3..169W Altcode: A new method of analyzing the emission spectrum of solar prominences is presented, in which the source function is allowed to vary with optical depth. Least-squares fitting of the observed profile determines simultaneously the optical depth T(0), the Doppler width, and the factor characterizing the variation of the source function. This method is applied to the early Balmer lines in ten prominences of Ye (1961). The results show that as the source function of the self-reversed H-alpha line increases towards the center of the prominence, the value at the center is 1.2 - 2.5 times the value at the edge. Neglect of this variation will give too large values of T(0). The degree of attenuation by self-absorption also depends on this variation. Discussion of the variation gives support to the view that the main exciting mechanism in solar prominences is the scattering of the incident radiation. Title: The oscillator strength of hydrogen lines Authors: Shi, Z. -X.; Wang, J. -X. Bibcode: 1983AcApS...3..327S Altcode: A formal expression is given for the dependence of hydrogen-line oscillator strength on departure form LTE, and a method is proposed for determining this departure in the various sublevels of the hydrogen atom in solar prominences. Results for 10 solar prominences are given. Finally, the possible implications of a smaller population in the 2p level than in the 2s level are discussed.