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Study on Spectral Variability of Black-Hole MHO Accretion Flow

黑洞MHO吸积流的光谱变异性研究

基本信息

批准号：
13640238
负责人：
MINESHIGE Shin
金额：
$ 2.24万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640238/
关键词：
black hole dynamic synchrotron simulation magnetic recommection X-ray binary active galactic nuclei Compton scattering 磁場ガンマ線バースト

项目摘要

Magnetohydrodynamical Accretion Flows and Jet around a Black HoleWe performed three-dimensional (3D) magnetohydrodynamical (MHD) simulations of radiatively inefficient accretion flow around black holes, and, for the first time, succeeded in producing a jet from a rotating torus threaded by weak, localized poloidal, magnetic fields. This jet is derived by vertically inflating toroidal fields ('magnetic tower') and has a two-component structure: weakly magnetized plasmas threaded with poloidal (vertical) fields are surrounded by strongly magnetized plasmas with toroidal fields. We also calculated the emergent spectra of the MHD flows, finding that the simulated MHD flows can account for the observed spectrum of Sagittarius A^* in the flaring state, although we need to restrict the emission region to be compact.Photon Trapping in Black-Hole Accretion FlowsSome Ultra-Luminous X-ray sources (ULXs} and narrow-line Seyfert 1 galaxies (NLS1s) show rather peculiar behavior in the X-ray H-R diagram (diagram on the disk temperature, and disk luminosity plane); namely, flow temperature decreases as luminosity increases. We carefully solved the radiative transfer equation in the accretion flow, finding that the behavior of ULXs and NLS1s can be understood. The reason is that hard photons originating from deep inside the flow are more effectively trapped and only soft photons can go out, when accretion rate exceeds the critical rate.

磁流体力学吸积流和黑洞周围的射流我们对黑洞周围辐射低效的吸积流进行了三维(3D)磁流体动力学(MHD)模拟，并首次成功地从旋转的环面上产生了喷流，该环面由微弱的局域极向磁场贯穿。这种喷流是由垂直膨胀的环向场(‘磁塔’)产生的，具有两个分量的结构：带有极向(垂直)场的弱磁化等离子体被具有环向场的强磁化等离子体包围。我们还计算了MHD流的出射光谱，发现模拟的MHD流可以解释人马座A^*在耀斑状态下的观测光谱，尽管我们需要限制发射区域的紧凑。黑洞吸积流中的光子陷阱一些超发光X射线源(ULXS)和窄线塞弗特1星系(NLS1s)在X射线H-R图(盘面温度和盘面光度平面上的图)上显示出相当特殊的行为，即流动温度随着光度的增加而降低。我们仔细求解了吸积流中的辐射传输方程，发现ULXs和NLS1s的行为是可以理解的。原因是，当吸积率超过临界速率时，源自流动深处的硬光子被更有效地捕获，只有软光子才能出去。