The Size, Shape, and Scattering of Sagittarius A* at 86GHz: First VLBI with ALMA
文献类型：期刊论文
| 作者 | Issaoun, S.6,7; Johnson, M. D.7; Blackburn, L.7; Brinkerink, C. D.6; Moscibrodzka, M.6; Chael, A.7; Goddi, C.6,8; Marti-Vidal, I.9; Wagner, J.10; Doeleman, S. S.7 |
| 刊名 | ASTROPHYSICAL JOURNAL
 |
| 出版日期 | 2019-01-20 |
| 卷号 | 871期号:1页码:17 |
| 关键词 | accretion, accretion disks galaxies: individual (Sgr A*) Galaxy: center techniques: interferometric |
| ISSN号 | 0004-637X |
| DOI | 10.3847/1538-4357/aaf732 |
| 英文摘要 | The Galactic center supermassive black hole Sagittarius A* (Sgr A*) is one of the most promising targets to study the dynamics of black hole accretion and outflow via direct imaging with very long baseline interferometry (VLBI). At 3.5 mm (86 GHz), the emission from Sgr A* is resolvable with the Global Millimeter VLBI Array (GMVA). We present the first observations of Sgr A* with the phased Atacama Large Millimeter/submillimeter Array (ALMA) joining the GMVA. Our observations achieve an angular resolution of similar to 87 mu as, improving upon previous experiments by a factor of two. We reconstruct a first image of the unscattered source structure of Sgr A* at 3.5 mm, mitigating the effects of interstellar scattering. The unscattered source has a major-axis size of 120 +/- 34 mu as (12 +/- 3.4 Schwarzschild radii) and a symmetrical morphology (axial ratio of 1.2(-0.2)(+0.3)), which is further supported by closure phases consistent with zero within 3 sigma. We show that multiple disk-dominated models of Sgr A* match our observational constraints, while the two jet-dominated models considered are constrained to small viewing angles. Our long-baseline detections to ALMA also provide new constraints on the scattering of Sgr A*, and we show that refractive scattering effects are likely to be weak for images of Sgr A* at 1.3 mm with the Event Horizon Telescope. Our results provide the most stringent constraints to date for the intrinsic morphology and refractive scattering of Sgr A*, demonstrating the exceptional contribution of ALMA to millimeter VLBI. |
| 资助项目 | ERC Synergy Grant BlackHoleCam: Imaging the Event Horizon of Black Holes[610058] ; National Science Foundation[AST-1126433] ; National Science Foundation[AST-1716536] ; Gordon and Betty Moore Foundation[GBMF-5278] ; John Templeton Foundation ; JSPS KAKENHI[JP18K03656] ; JSPS KAKENHI[JP18H03721] ; National Youth Thousand Talents Program of China ; Max-Planck Partner Group ; DGAPA, UNAM[IN112417] ; CONACyT, Mexico ; National Research Foundation of Korea (NRF)[NRF-2015H1A2A1033752] ; black hole initiative at Harvard University |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000456323800001 |
| 出版者 | IOP PUBLISHING LTD |
| 源URL | [http://119.78.226.72/handle/331011/31991]  |
| 专题 | 中国科学院上海天文台 |
| 通讯作者 | Issaoun, S. |
| 作者单位 | 1.Univ Nacl Autonoma Mexico, Inst Astron, Apartado Postal 70-264, Mexico City 04510, DF, Mexico 2.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China 3.Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 XH Amsterdam, Netherlands 4.Observ Yebes IGN, Apartado 148, E-19180 Yebes, Spain 5.Univ Arizona, 933 North Cherry Ave, Tucson, AZ 85721 USA 6.Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands 7.Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA 8.Leiden Univ, Leiden Observ, ALLEGRO, POB 9513, NL-2300 RA Leiden, Netherlands 9.Chalmers Univ Technol, Dept Space Earth & Environm, Onsala Space Observ, SE-43992 Onsala, Sweden 10.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany |
| 推荐引用方式 GB/T 7714 | Issaoun, S.,Johnson, M. D.,Blackburn, L.,et al. The Size, Shape, and Scattering of Sagittarius A* at 86GHz: First VLBI with ALMA[J]. ASTROPHYSICAL JOURNAL,2019,871(1):17. |
| APA | Issaoun, S..,Johnson, M. D..,Blackburn, L..,Brinkerink, C. D..,Moscibrodzka, M..,...&Zhao, G. -Y..(2019).The Size, Shape, and Scattering of Sagittarius A* at 86GHz: First VLBI with ALMA.ASTROPHYSICAL JOURNAL,871(1),17. |
| MLA | Issaoun, S.,et al."The Size, Shape, and Scattering of Sagittarius A* at 86GHz: First VLBI with ALMA".ASTROPHYSICAL JOURNAL 871.1(2019):17. |
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来源：上海天文台
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