X-ray polarization evidence for a 200-year-old flare of Sgr A*
X-ray polarization evidence for a 200-year-old flare of Sgr A*
复制标题
200 年前 Sgr A* 耀斑的 X 射线偏振证据
DOI：
10.1038/s41586-023-06064-x
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发表时间：
2023
期刊：
影响因子：
64.8
通讯作者：
Costa, Enrico
中科院分区：
文献类型：
--
作者：
Marin, Frédéric;Churazov, Eugene;Khabibullin, Ildar;Ferrazzoli, Riccardo;Di Gesu, Laura;Barnouin, Thibault;Di Marco, Alessandro;Middei, Riccardo;Vikhlinin, Alexey;Costa, Enrico
银河系中心有一个质量约为 4 百万太阳质量的黑洞（人马座 A*(Sgr A)），目前非常静止，其光度比活跃星系核低多个数量级。银河系中心区域的致密气体反射来自 Sgr A* 的 X 射线，为研究其过去数百年和数千年的耀斑活动提供了一种手段。从 Sgr A* 附近的巨型分子云观测到的 X 射线连续谱的形状和强荧光铁线与反射场景 - 一致。如果这种解释是正确的，则反射的连续发射应该是偏振的。在这里，我们报告了使用成像 X 射线偏振测量探测器对银河系中心分子云方向的偏振 X 射线发射的观测结果。我们测得偏振度为31%±11%，偏振角为-48°±11°。偏振角与 Sgr A* 作为主要发射源一致，并且偏振度意味着大约 200 年前，Sgr A* 的 X 射线光度与 Seyfert 星系的 X 射线光度短暂相当。
The centre of the Milky Way Galaxy hosts a black hole with a solar mass of about 4 million (Sagittarius A*(Sgr A)) that is very quiescent at present with a luminosity many orders of magnitude below those of active galactic nuclei. Reflection of X-rays from Sgr A*by dense gas in the Galactic Centre region offers a means to study its past flaring activity on timescales of hundreds and thousands of years. The shape of the X-ray continuum and the strong fluorescent iron line observed from giant molecular clouds in the vicinity of Sgr A*are consistent with the reflection scenario, –. If this interpretation is correct, the reflected continuum emission should be polarized. Here we report observations of polarized X-ray emission in the direction of the molecular clouds in the Galactic Centre using the Imaging X-ray Polarimetry Explorer. We measure a polarization degree of 31% ± 11%, and a polarization angle of −48° ± 11°. The polarization angle is consistent with Sgr A*being the primary source of the emission, and the polarization degree implies that some 200 years ago, the X-ray luminosity of Sgr A*was briefly comparable to that of a Seyfert galaxy.