银河系中心的反射星云：软X射线成像偏振测量的情况
Reflection nebulae in the Galactic Center: the case for soft X-ray imaging polarimetry
摘要：
围绕银河系中心超大质量黑洞Sgr A* 的6.4 keV明亮巨分子云的辐射和荧光的起源仍然是个谜。检验Sgr A* 过去活跃期的理论需要X射线偏振测定法。在本文中，我们将展示现代成像偏振仪如何彻底改变我们对银河系中心的理解。通过蒙特卡罗模拟，我们产生了一个4-8千电子伏的银河系中心的偏振图，重点是由Sgr B1，Sgr B2，G0.11-0.11，桥E，桥D，桥B2，MC 2，MC 1，Sgr C3，Sgr C2和Sgr C1产生的偏振签名。我们估计由此产生的极化，包括偏振通量稀释的扩散等离子体发射检测到的GC，并模拟偏振图，现代偏振探测器将获得假设的任务原型的性能。本文研究的11个反射星云呈现出各种偏振特征，从几乎非偏振到高度偏振（约77%）的通量。在我们的模拟中的一个主要改进是增加了一个扩散，非极化等离子体发射，强烈影响软X射线极化通量。稀释因子在50% -70%的范围内，使得即使在现代偏振测量的背景下也不太可能观察到桥结构。最好的靶标是Sgr B和Sgr C复合物以及G0.11-0.11云。对Sgr B复合体的几百千秒的探索性观测将允许对偏振的显著检测，并足以获得关于主要辐射源的线索。一个更雄心勃勃的计划（几个M）映射巨大的分子云，然后可以进行非常精确的探测Sgr A* 的湍流历史，并对周围气体的成分和三维位置施加重要的限制。
英文摘要：
The origin of irradiation and fluorescence of the 6.4 keV bright giant molecular clouds surrounding Sgr A*, the central supermassive black hole of our Galaxy, remains enigmatic. Testing the theory of a past active period of Sgr A* requires X-ray polarimetry. In this paper, we show how modern imaging polarimeters could revolutionize our understanding of the Galactic Center. Through Monte Carlo modeling, we produce a 4-8 keV polarization map of the Galactic Center, focusing on the polarimetric signature produced by Sgr B1, Sgr B2, G0.11-0.11, Bridge E, Bridge D, Bridge B2, MC2, MC1, Sgr C3, Sgr C2, and Sgr C1. We estimate the resulting polarization, include polarized flux dilution by the diffuse plasma emission detected toward the GC, and simulate the polarization map that modern polarimetric detectors would obtain assuming the performances of a mission prototype. The eleven reflection nebulae investigated in this paper present a variety of polarization signatures, ranging from nearly unpolarized to highly polarized (about 77%) fluxes. A major improvement in our simulation is the addition of a diffuse, unpolarized plasma emission that strongly impacts soft X-ray polarized fluxes. The dilution factor is in the range 50% - 70%, making the observation of the Bridge structure unlikely even in the context of modern polarimetry. The best targets are the Sgr B and Sgr C complexes, and the G0.11-0.11 cloud. An exploratory observation of a few hundred kilo-seconds of the Sgr B complex would allow a significant detection of the polarization and be sufficient to derive hints on the primary source of radiation. A more ambitious program (few Ms) of mapping the giant molecular clouds could then be carried out to probe with great precision the turbulent history of Sgr A*, and place important constraints on the composition and three-dimensional position of the surrounding gas.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
