Search Publications
Are Seyfert 2 Galaxies without Polarized Broad Emission Lines More Obscured?
Wang, Jun-Xian; Jiang, Peng; Shu, Xin-Wen
New XMM-Newton data of seven Seyfert 2 galaxies with optical spectropolarimetric observations are presented. An analysis of the 0.5-10 keV spectra shows that four Seyfert 2 galaxies with polarized broad lines (PBLs) are absorbed by NH<1024 cm-2, while two of three Seyfert 2 galaxies without PBLs show evidence of…
Formation of Transient Coronal Holes during the Eruption of a Quiescent Filament and its Overlying Sigmoid
Yang, Li-Heng; Jiang, Yun-Chun; Ren, Dong-Bai
By using Hα, He I 10830, EUV and soft X-ray (SXR) data, we examined a filament eruption that occurred on a quiet-sun region near the center of the solar disk on 2006 January 12, which disturbed a sigmoid overlying the filament channel observed by the GOES-12 SXR Imager (SXI), and led to the eruption of the sigmoid. The event was associated with a …
Revisiting the Local Kinematics of the Milky Way using the New Hipparcos Data
Zhu, Zi; Yuan, Fang-Ting; Kong, Da-Li
With the new Hipparcos data recently released, we reexamine the kinematics in the solar neighborhood. Two different populations of objects, namely the thin-disk O-B5 stars and the thick-disk K-M giants, are selected for tracing the kinematical parameters of the Galaxy. Using a 3-D kinematical model, the components of the solar motion and the Oort …
The Structure of Narrow-Line Region in LINERs
Wang, Ting-Gui; Dai, Hai-Feng
Low-ionization nuclear emission regions (LINERs) are present in a large fraction of local galaxies, while their connection to the more luminous active galactic nuclei (AGN) remains elusive. We analyze the narrow band images obtained by the Hubble Space Telescope (HST) in Hα+[NII] and/or [OIII] band for 23 LINERs and low luminosity Seyfert galaxies…
Speed Distributions of CMEs in Cycle 23 at Low and High Latitudes
Gao, Peng-Xin; Li, Ke-Jun
We analyzed the speed (v) distributions of 11584 coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph Experiment on board the Solar and Heliospheric Observatory (SOHO/LASCO) in cycle 23 from 1996 to 2006. We find that the speed distributions for high-latitude (HL) and low-latitude (LL) CME events are nearly ident…
Geometry of Broad Line Regions of Active Galactic Nuclei
Lü, Xiao-Rong
It has long remained an open question as to the geometry of the broad line region (BLR) in active galactic nuclei (AGNs). The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of prob…
Circumnuclear Star Forming Activity in NGC 3982
Gu, Qiu-Sheng; Wang, Yi-Peng; Zhang, Shui-Nai
We present a study of the nearby Seyfert galaxy NGC 3982 using optical, infrared and X-ray data acquired by SDSS, Spitzer and Chandra. Our main results are as follows: (1) A simple stellar population synthesis on the nuclear and circumnuclear SDSS spectra gives unambiguous evidence of young stellar components in both the nuclear and circumnuclear …
Magnetic Properties of Metric Noise Storms Associated with Coronal Mass Ejections
Wang, Jing-Xiu; Wen, Ya-Yuan; Zhang, Yu-Zong
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 …
Observational Features of Large-Scale Structures as Revealed by the Catastrophe Model of Solar Eruptions
Lin, Jun
Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceasing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in…
Estimating Black Hole Masses of AGNs using Ultraviolet Emission Line Properties
Wang, Ran; Wu, Xue-Bing; Kong, Min-Zhi +1 more
Based on measured broad line region sizes in the reverberation-mapping AGN sample, two new empirical relations are introduced to estimate the central black hole masses of radio-loud high-redshift (z>0.5) AGNs. First, using the archival IUE/HST spectroscopy data at UV band for the reverberation-mapping objects, we obtained two new empirical rela…