Resolved magnetic-field structure and variability near the event horizon of Sagittarius A*
Resolved magnetic-field structure and variability near the event horizon of Sagittarius A*
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DOI：
10.1126/science.aac7087
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发表时间：
2015-12
期刊：
影响因子：
56.9
通讯作者：
Michael D. Johnson;V. Fish;S. Doeleman;D. Marrone;R. Plambeck;J. Wardle;K. Akiyama;K. Asada;
中科院分区：
文献类型：
--
作者：
Michael D. Johnson;V. Fish;S. Doeleman;D. Marrone;R. Plambeck;J. Wardle;K. Akiyama;K. Asada;
长期以来，天文学家一直试图研究黑洞的视界--黑洞周围任何东西都无法逃脱的边界--视界附近的磁场。Johnson等人。使用复杂的干涉技术将来自世界各地的毫米波长望远镜的数据结合在一起。他们在银河系中心的超大质量黑洞SgrA*的视界外测量了偏振。极化是黑洞周围吸积盘中产生的有序磁场的特征。这些结果有助于解释黑洞如何吸积气体并将物质喷射到其周围。科学，这个问题，第1242页，超大质量黑洞视界周围的磁场已经被探索。在黑洞附近，磁化吸积盘的差异旋转被认为会产生一种不稳定，放大弱磁场，驱动吸积和外流。这些磁场自然会引起观测到的星系核心的同步辐射和相对论喷流的形成，但到目前为止还没有观测到能够解决预期的地平线尺度的磁场结构。我们报告了1.3毫米波长的干涉观测，它在空间上解析了来自银河中心超大质量黑洞--人马座A*的线偏振辐射。我们已经在视界附近发现了偏序磁场的证据，其尺度为~6 Schwarzschild半径，我们已经探测到并定位了与这些磁场相关的小时内变异性。
Magnetic fields near the event horizon Astronomers have long sought to examine a black hole's event horizon—the boundary around the black hole within which nothing can escape. Johnson et al. used sophisticated interferometry techniques to combine data from millimeter-wavelength telescopes around the world. They measured polarization just outside the event horizon of Sgr A*, the supermassive black hole at the center of our galaxy, the Milky Way. The polarization is a signature of ordered magnetic fields generated in the accretion disk around the black hole. The results help to explain how black holes accrete gas and launch jets of material into their surroundings. Science, this issue p. 1242 Magnetic fields around the event horizon of a supermassive black hole have been probed. Near a black hole, differential rotation of a magnetized accretion disk is thought to produce an instability that amplifies weak magnetic fields, driving accretion and outflow. These magnetic fields would naturally give rise to the observed synchrotron emission in galaxy cores and to the formation of relativistic jets, but no observations to date have been able to resolve the expected horizon-scale magnetic-field structure. We report interferometric observations at 1.3-millimeter wavelength that spatially resolve the linearly polarized emission from the Galactic Center supermassive black hole, Sagittarius A*. We have found evidence for partially ordered magnetic fields near the event horizon, on scales of ~6 Schwarzschild radii, and we have detected and localized the intrahour variability associated with these fields.