The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole
文献类型：期刊论文
| 作者 | Narayan,Ramesh2,76; Palumbo,Daniel C. M.2,76; Johnson,Michael D.2,76; Gelles,Zachary2,76; Himwich,Elizabeth2,3; Chang,Dominic O.2,76; Ricarte,Angelo2,76; Dexter,Jason4; Gammie,Charles F.5,6; Chael,Andrew A.7 |
| 刊名 | The Astrophysical Journal
 |
| 出版日期 | 2021-05-01 |
| 卷号 | 912期号:1 |
| ISSN号 | 0004-637X |
| 关键词 | Accretion Black holes Polarimetry Magnetic fields |
| DOI | 10.3847/1538-4357/abf117 |
| 英文摘要 | Abstract Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov and conservation of the Walker–Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images. |
| 语种 | 英语 |
| 出版者 | The American Astronomical Society |
| WOS记录号 | IOP:0004-637X-912-1-ABF117 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/58258]  |
| 专题 | 中国科学院国家天文台 |
| 作者单位 | 1.National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, People’s Republic of China 2.Black Hole Initiative at Harvard University, 20 Garden Street, Cambridge, MA 02138, USA 3.Center for the Fundamental Laws of Nature, Harvard University, Cambridge, MA 02138, USA 4.JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309, USA 5.Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801, USA 6.Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801, USA 7.Princeton Center for Theoretical Science, Jadwin Hall, Princeton University, Princeton, NJ 08544, USA 8.Massachusetts Institute of Technology Haystack Observatory, 99 Millstone Road, Westford, MA 01886, USA 9.National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 10.Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, E-18008 Granada, Spain |
| 推荐引用方式 GB/T 7714 | Narayan,Ramesh,Palumbo,Daniel C. M.,Johnson,Michael D.,et al. The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole[J]. The Astrophysical Journal,2021,912(1). |
| APA | Narayan,Ramesh.,Palumbo,Daniel C. M..,Johnson,Michael D..,Gelles,Zachary.,Himwich,Elizabeth.,...&Zhao,Shan-Shan.(2021).The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole.The Astrophysical Journal,912(1). |
| MLA | Narayan,Ramesh,et al."The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole".The Astrophysical Journal 912.1(2021). |
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来源：国家天文台
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