The Intrinsic Structure of Sagittarius A* at 1.3 cm and 7 mm
文献类型：期刊论文
| 作者 | Cho, Ilje1,2,3; Zhao, Guang-Yao1,3; Kawashima, Tomohisa4; Kino, Motoki5,6; Akiyama, Kazunori5,7,8; Johnson, Michael D.8,9; Issaoun, Sara9,10; Moriyama, Kotaro7,11; Cheng, Xiaopeng1; Algaba, Juan-Carlos12 |
| 刊名 | Astrophysical Journal
 |
| 出版日期 | 2022-02-01 |
| 卷号 | 926期号:2页码:108 |
| ISSN号 | 0004-637X |
| 关键词 | magnetically arrested accretion base-line interferometry scatter-broadened image supermassive black-hole event-horizon galactic-center radio-source vlbi observations nonthermal electrons synchrotron emission Astronomy & Astrophysics |
| DOI | 10.3847/1538-4357/ac4165 |
| 产权排序 | 25 |
| 文献子类 | Article |
| 英文摘要 | Sagittarius A* (Sgr A*), the Galactic Center supermassive black hole (SMBH), is one of the best targets in which to resolve the innermost region of an SMBH with very long baseline interferometry (VLBI). In this study, we have carried out observations toward Sgr A* at 1.349 cm (22.223 GHz) and 6.950 mm (43.135 GHz) with the East Asian VLBI Network, as a part of the multiwavelength campaign of the Event Horizon Telescope (EHT) in 2017 April. To mitigate scattering effects, the physically motivated scattering kernel model from Psaltis et al. (2018) and the scattering parameters from Johnson et al. (2018) have been applied. As a result, a single, symmetric Gaussian model well describes the intrinsic structure of Sgr A* at both wavelengths. From closure amplitudes, the major-axis sizes are similar to 704 +/- 102 mu as (axial ratio similar to 1.19(-0.19)(+0.24)) and similar to 300 +/- 25 mu as (axial ratio similar to 1.28 +/- 0.2) at 1.349 cm and 6.95 mm, respectively. Together with a quasi-simultaneous observation at 3.5 mm (86 GHz) by Issaoun et al. (2019), we show that the intrinsic size scales with observing wavelength as a power law, with an index similar to 1.2 +/- 0.2. Our results also provide estimates of the size and compact flux density at 1.3 mm, which can be incorporated into the analysis of the EHT observations. In terms of the origin of radio emission, we have compared the intrinsic structures with the accretion flow scenario, especially the radiatively inefficient accretion flow based on the Keplerian shell model. With this, we show that a nonthermal electron population is necessary to reproduce the source sizes. |
| URL标识 | 查看原文 |
| 语种 | 英语 |
| WOS记录号 | WOS:000821505000001 |
| 源URL | [http://ir.xao.ac.cn/handle/45760611-7/5129]  |
| 专题 | 星系宇宙学研究团组 射电天文研究室_利用南山26米射电望远镜观测数据的文章 |
| 作者单位 | 1.Korea Astronomy and Space Science Institute, Daedeok-daero 776, Yuseong-gu, Daejeon 34055, Republic of Korea; 2.University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113, Republic of Korea; 3.Instituto de Astrofísica de Andalucía—CSIC, Glorieta de la Astronomía s/n, E-18008 Granada, Spain; gyzhao@iaa.es; 4.Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582, Japan; 5.National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; 6.Kogakuin University of Technology & Engineering, Academic Support Center, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan; 7.Massachusetts Institute of Technology Haystack Observatory, 99 Millstone Road, Westford, MA 01886, USA; 8.Black Hole Initiative at Harvard University, 20 Garden Street, Cambridge, MA 02138, USA; 9.Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA; 10.Department of Astrophysics, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands; |
| 推荐引用方式 GB/T 7714 | Cho, Ilje,Zhao, Guang-Yao,Kawashima, Tomohisa,et al. The Intrinsic Structure of Sagittarius A* at 1.3 cm and 7 mm[J]. Astrophysical Journal,2022,926(2):108. |
| APA | Cho, Ilje.,Zhao, Guang-Yao.,Kawashima, Tomohisa.,Kino, Motoki.,Akiyama, Kazunori.,...&Chen, Zhong.(2022).The Intrinsic Structure of Sagittarius A* at 1.3 cm and 7 mm.Astrophysical Journal,926(2),108. |
| MLA | Cho, Ilje,et al."The Intrinsic Structure of Sagittarius A* at 1.3 cm and 7 mm".Astrophysical Journal 926.2(2022):108. |
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