Kinetic Simulations of Radiative Magnetic Reconnection in the Coronae of Accreting Black Holes
Kinetic Simulations of Radiative Magnetic Reconnection in the Coronae of Accreting Black Holes
复制标题
吸积黑洞日冕中辐射磁重联的动力学模拟
DOI：
10.3847/1538-4357/aba622
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
A. Beloborodov
中科院分区：
文献类型：
--
作者：
L. Sironi;A. Beloborodov
我们执行二维和三维粒子在细胞内的重联模拟在强康普顿冷却磁主导的等离子体。在这种条件下，磁重联可以在黑洞周围的吸积盘日冕中进行，通过复合产生硬x射线。我们的模拟表明，重联层中的大部分等离子体由于康普顿损失而保持低温，并被锁定在具有小热压的磁控制等离子体中。康普顿阻力清除等离子体内部的空腔，也影响它们的整体运动。然而，与非辐射重联相比，这些效应对重联速率和等离子体大小分布的影响较弱。这表明，在两种情况下，重联动力学受相似的磁应力控制，受热压的影响较小。我们研究了辐射重联激发粒子的能量分布，并观察到两个不同的组成部分：(1)一个温和的相对论性峰，它是由冷却等离子体的大块运动引起的。该元件接收大部分耗散重联功率，并主导输出x射线发射。峰具有准麦克斯韦形状，有效温度为~ 100 keV。因此，它模拟了以前用来拟合吸积黑洞的硬态光谱的热复合体。(2)高能尾部，接收重连接耗散功率的约20%。它由在x点被脉冲加速的粒子填充，或者被从x点快速流出的粒子“拾取”。高能粒子立即冷却，它们的逆康普顿发射解释了在Cyg X-1的硬态中检测到的MeV光谱尾巴。我们的第一性原理模拟支持磁重联作为一种机制，为吸积黑洞磁主导区域的硬x射线发射提供动力。
We perform 2D and 3D particle-in-cell simulations of reconnection in magnetically dominated e± plasmas subject to strong Compton cooling. Magnetic reconnection under such conditions can operate in accretion disk coronae around black holes, which produce hard X-rays through Comptonization. Our simulations show that most of the plasma in the reconnection layer is kept cold by Compton losses and locked in magnetically dominated plasmoids with a small thermal pressure. Compton drag clears cavities inside plasmoids and also affects their bulk motions. These effects, however, weakly change the reconnection rate and the plasmoid size distribution from those in nonradiative reconnection. This demonstrates that the reconnection dynamics is governed by similar magnetic stresses in both cases and weakly affected by thermal pressure. We examine the energy distribution of particles energized by radiative reconnection and observe two distinct components: (1) A mildly relativistic peak, which results from bulk motions of cooled plasmoids. This component receives most of the dissipated reconnection power and dominates the output X-ray emission. The peak has a quasi-Maxwellian shape with an effective temperature of ∼100 keV. Thus, it mimics thermal Comptonization used previously to fit hard-state spectra of accreting black holes. (2) A high-energy tail, which receives ∼20% of the dissipated reconnection power. It is populated by particles accelerated impulsively at X-points or “picked up” by fast outflows from X-points. The high-energy particles immediately cool, and their inverse Compton emission explains the MeV spectral tail detected in the hard state of Cyg X-1. Our first-principle simulations support magnetic reconnection as a mechanism powering hard X-ray emission from magnetically dominated regions of accreting black holes.
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DOI：
10.3847/1538-4357/aac820
发表时间：
2018-03
期刊：
The Astrophysical Journal
影响因子：
--
作者：
D. Ball;L. Sironi;F. Özel
通讯作者：
D. Ball;L. Sironi;F. Özel
影响因子：
4.8
作者：
K. Chatterjee;M. Liska;A. Tchekhovskoy;S. Markoff
通讯作者：
K. Chatterjee;M. Liska;A. Tchekhovskoy;S. Markoff
DOI：
10.3847/1538-4357/ab03d7
发表时间：
2019-01
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Rowan;L. Sironi;R. Narayan
通讯作者：
M. Rowan;L. Sironi;R. Narayan
DOI：
10.3847/1538-4357/aa9380
发表时间：
2017-08
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Rowan;L. Sironi;R. Narayan
通讯作者：
M. Rowan;L. Sironi;R. Narayan