Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. I. X-Ray Spectral and Long-term Variability Analyses
文献类型：期刊论文
| 作者 | Li,Junyao2,3; Xue,Yongquan2,3; Sun,Mouyuan2,3; Liu,Teng4; Vito,Fabio5,6; Brandt,William N.7,8,9; Hughes,Thomas M.2,3,10,11; Yang,Guang7,8; Tozzi,Paolo12; Zhu,Shifu7,8 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2019-05-16 |
| 卷号 | 877期号:1 |
| 关键词 | galaxies: active galaxies: nuclei quasars: general X-rays: galaxies |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/ab184b |
| 英文摘要 | Abstract We present a detailed X-ray spectral analysis of 1152 active galactic nuclei (AGNs) selected in the Chandra Deep Fields (CDFs), in order to identify highly obscured AGNs ( ?>? ). By fitting spectra with physical models, 436 (38%) sources with are confirmed to be highly obscured, including 102 Compton-thick (CT) candidates. We propose a new hardness ratio measure of the obscuration level that can be used to select highly obscured AGN candidates. The completeness and accuracy of applying this method to our AGNs are 88% and 80%, respectively. The observed log N?log S relation favors cosmic X-ray background models that predict moderate (i.e., between optimistic and pessimistic) CT number counts. Nineteen percent (6/31) of our highly obscured AGNs that have optical classifications are labeled as broad-line AGNs, suggesting that, at least for part of the AGN population, the heavy X-ray obscuration is largely a line-of-sight effect, i.e., some high column density clouds on various scales (but not necessarily a dust-enshrouded torus) along our sight line may obscure the compact X-ray emitter. After correcting for several observational biases, we obtain the intrinsic ?distribution and its evolution. The CT/highly obscured fraction is roughly 52% and is consistent with no evident redshift evolution. We also perform long-term (≈17 yr in the observed frame) variability analyses for 31 sources with the largest number of counts available. Among them, 17 sources show flux variabilities: 31% (5/17) are caused by the change of , 53% (9/17) are caused by the intrinsic luminosity variability, 6% (1/17) are driven by both effects, and 2 are not classified owing to large spectral fitting errors. |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-637X-877-1-AB184B |
| 出版者 | The American Astronomical Society |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/26319]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.Department of Physics, Anhui Normal University, Wuhu, Anhui, 241000, People’s Republic of China 2.CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei 230026, People’s Republic of China; lijunyao@mail.ustc.edu.cn 3.School of Astronomy and Space Science, University of Science and Technology of China, Hefei 230026, People’s Republic of China; xuey@ustc.edu.cn 4.Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München, Germany 5.Instituto de Astrofisica and Centro de Astroingenieria, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22, Chile 6.Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS, Beijing 100012, People’s Republic of China 7.Department of Astronomy & Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802, USA 8.Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA 9.Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA 10.CAS South America Center for Astronomy, China-Chile Joint Center for Astronomy, Camino El Observatorio #1515, Las Condes, Santiago, Chile |
| 推荐引用方式 GB/T 7714 | Li,Junyao,Xue,Yongquan,Sun,Mouyuan,et al. Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. I. X-Ray Spectral and Long-term Variability Analyses[J]. The Astrophysical Journal,2019,877(1). |
| APA | Li,Junyao.,Xue,Yongquan.,Sun,Mouyuan.,Liu,Teng.,Vito,Fabio.,...&Shu,Xinwen.(2019).Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. I. X-Ray Spectral and Long-term Variability Analyses.The Astrophysical Journal,877(1). |
| MLA | Li,Junyao,et al."Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. I. X-Ray Spectral and Long-term Variability Analyses".The Astrophysical Journal 877.1(2019). |
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