X-Ray Diagnostics of Giant Molecular Clouds in the Galactic Center Region and Past Activity of Sgr A*
X-Ray Diagnostics of Giant Molecular Clouds in the Galactic Center Region and Past Activity of Sgr A*
复制标题
银河系中心区域巨型分子云的 X 射线诊断和 Sgr A* 过去的活动
DOI：
10.1088/0004-637x/740/2/103
复制
发表时间：
2011
影响因子：
4.9
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
H.Odaka;et al
强烈的铁荧光在6.4千电子伏和硬X射线发射的巨型分子云在银河系中心区域已被解释为过去爆发的Sgr A* 超大质量黑洞的反射。仔细处理光子在复杂几何结构中的多重相互作用对于模拟来自稠密云的再处理发射是必不可少的。我们开发了一个新的计算框架的X射线反射的分子云的Monte Carlo模拟的基础上准确解释高质量的观测数据。通过利用这个模拟框架，我们提出了第一次计算的形态和光谱的反射X射线发射的几个现实模型的Sgr B2，这是最大的分子云在我们的银河系。20 keV以上的散射硬X射线的形态与铁荧光的形态显著不同，这是因为它们对云的密集区域具有很大的穿透力，可以探测云的结构。高分辨率光谱提供了对铁线的定量评估，包括其康普顿肩，以限制云的质量和化学成分以及照明源的光度。在不久的将来，这些预测可以通过未来的X射线飞行任务，如努斯塔（硬X射线）和ASTRO-H（既有铁谱线又有硬X射线）进行检验。
Strong iron fluorescence at 6.4 keV and hard-X-ray emissions from giant molecular clouds in the Galactic center region have been interpreted as reflections of a past outburst of the Sgr A* supermassive black hole. Careful treatment of multiple interactions of photons in a complicated geometry is essential to modeling the reprocessed emissions from the dense clouds. We develop a new calculation framework of X-ray reflection from molecular clouds based on Monte Carlo simulations for accurate interpretation of high-quality observational data. By utilizing this simulation framework, we present the first calculations of morphologies and spectra of the reflected X-ray emission for several realistic models of Sgr B2, which is the most massive molecular cloud in our Galaxy. The morphology of scattered hard X-rays above 20 keV is significantly different from that of iron fluorescence due to their large penetrating power into dense regions of the cloud, probing the structure of the cloud. High-resolution spectra provide quantitative evaluation of the iron line including its Compton shoulder to constrain the mass and the chemical composition of the cloud as well as the luminosity of the illuminating source. These predictions can be checked in the near future with future X-ray missions such as NuStar (hard X-rays) and ASTRO-H (both iron lines and hard X-rays).