NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY
NEW EVIDENCE FOR HIGH ACTIVITY OF THE SUPERMASSIVE BLACK HOLE IN OUR GALAXY
复制标题
DOI：
10.1088/2041-8205/739/2/l52
复制
发表时间：
2011-09
期刊：
影响因子：
--
通讯作者：
M. Nobukawa;S. G. Ryu;T. Tsuru;K. Koyama
中科院分区：
文献类型：
--
作者：
M. Nobukawa;S. G. Ryu;T. Tsuru;K. Koyama
在 2005 年和 2009 年的两次朱雀观测中，发现了人马座 B (Sgr B) 区域中性铁的突出 K 壳层发射线（以下简称 Fe i-K 线）和来自人马座 B (Sgr B) 区域分子云 (MC) 的硬连续谱 X 射线。Fe i-K 线的 X 射线通量与硬连续谱通量相关，在四年内减少了 0.4-0.5 倍，几乎等于光传播的速度。跨MC。由于来自外部源的 X 射线耀斑的荧光和汤姆逊散射，快速且相关的时间变化、Fe i-K 线的等效宽度以及 Fe i 的 K 边缘吸收深度始终可以通过“X 射线回波”来解释。 X 射线耀斑所需的通量取决于到 MC 的距离及其持续时间。即使对于距离最短的情况，通量也比最亮的银河 X 射线源的通量还要大。基于这些事实，我们得出结论，超大质量黑洞Sgr A*在几百年前表现出巨大的耀斑，其光度超过4×1039 erg s−1。来自人马座 B 的“X 射线回波”距离人马座 A* 几百光年，现已到达地球。
Prominent K-shell emission lines of neutral iron (hereafter Fe i-K lines) and hard-continuum X-rays from molecular clouds (MCs) in the Sagittarius B (Sgr B) region were found in two separate Suzaku observations in 2005 and 2009. The X-ray flux of the Fe i-K lines decreased in correlation with the hard-continuum flux by a factor of 0.4–0.5 in four years, which is almost equal to the light traveling across the MCs. The rapid and correlated time variability, the equivalent width of the Fe i-K lines, and the K edge absorption depth of Fe i are consistently explained by “X-ray echoes” due to the fluorescent and Thomson scattering of an X-ray flare from an external source. The required flux of the X-ray flare depends on the distance to the MCs and its time duration. Even for a case with a minimum distance, the flux is larger than those of the brightest Galactic X-ray sources. Based on these facts, we conclude that the supermassive black hole Sgr A* exhibited a large flare a few hundred years ago with a luminosity of more than 4 × 1039 erg s−1. The “X-ray echo” from Sgr B, located a few hundred light-years from Sgr A*, has now reached the Earth.