论文标题
SGR A*的X射线监测的延续：确认明亮的耀斑率的增加
Continuation of the X-ray monitoring of Sgr A*: the increase in bright flaring rate confirmed
论文作者
论文摘要
超大型黑洞Sagittarius A*（SGR A*）位于银河系的动态中心。在最近对使用Chandra，XMM-Newton和Swift数据从1999年到2015年的SGR A*的X射线爆炸活性的研究中，一直有人认为，明亮的耀斑速率从2014年8月31日起增加了1.4ms）。我们在Chandra数据中检测到了9张耀斑，并在Swift数据中添加了5个耀斑，并将其添加到107个先前检测到的耀斑中。我们使用一种新方法计算了针对灵敏度偏差校正的耀斑通量和持续时间的固有分布，该方法使我们能够考虑到耀斑通量和持续时间的误差。从这个内在分布中，我们确定了每个Chandra，XMM-Newton和Swift观察的平均耀斑检测效率。在纠正了该效率的每个观测暴露后，我们在串联的火炬到达时间上应用了贝叶斯块算法。与上述研究一样，我们还搜索了可能导致耀斑变化的通量和通量阈值。我们通过计算每个通量和通量范围的平均耀斑检测效率来改善先前的方法。贝叶斯块算法未检测到121张耀斑的耀斑速率发生任何重大变化。但是，我们发现自2014年8月30日以来发生的最发光和最有活力的耀斑的耀斑速率的增加约为三倍。SGRA*的X射线活动已增加了四年多。需要有关SGR A*的整体近红外和无线电行为的其他研究，以对黑洞的多波长活性取得强烈的结果。
The supermassive black hole Sagittarius A* (Sgr A*) is located at the dynamical center of the Milky Way. In a recent study of the X-ray flaring activity from Sgr A* using Chandra, XMM-Newton and Swift data from 1999 to 2015, it has been argued that the bright flaring rate has increased from 2014 Aug. 31 while the faint flaring rate decreased from around 2013 Aug. We tested the persistence of these changes in the flaring rates with new X-ray data of Sgr A* obtained in 2016-2018 (total exposure of 1.4Ms). We detected 9 flares in the Chandra data and 5 flares in the Swift data that we added to the set of 107 previously detected flares. We computed the intrinsic distribution of flare fluxes and durations corrected for the sensitivity bias using a new method that allowed us to take the error on the flare fluxes and durations into account. From this intrinsic distribution, we determined the average flare detection efficiency for each Chandra, XMM-Newton, and Swift observation. After correcting each observational exposure for this efficiency, we applied the Bayesian blocks algorithm on the concatenated flare arrival times. As in the above-mentioned study, we also searched for a flux and fluence threshold that might lead to a change in flaring rate. We improved the previous method by computing the average flare detection efficiencies for each flux and fluence range. The Bayesian block algorithm did not detect any significant change in flaring rate of the 121 flares. However, we detected an increase by a factor of about three in the flaring rate of the most luminous and most energetic flares that have occurred since 2014 Aug. 30. The X-ray activity of Sgr A* has increased for more than four years. Additional studies about the overall near-infrared and radio behavior of Sgr A* are required to draw strong results on the multiwavelength activity of the black hole.
