Comptonization by reconnection plasmoids in black hole coronae II: Electron-ion plasma
Comptonization by reconnection plasmoids in black hole coronae II: Electron-ion plasma
复制标题
黑洞日冕中重联等离子体团的复合化 II：电子离子等离子体
DOI：
10.1093/mnras/stac2730
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发表时间：
2022
影响因子：
4.8
通讯作者：
Beloborodov, Andrei M.
中科院分区：
文献类型：
--
作者：
Sridhar, Navin;Sironi, Lorenzo;Beloborodov, Andrei M.
我们进行2D粒子在细胞中的电子-离子等离子体的磁重联受到强康普顿冷却模拟和计算的X射线光谱产生的这个过程。模拟了在黑洞周围吸积盘日冕中预期的磁化强度为1 ≤ σ ≤ 3（定义为磁张力与等离子体静止质量能量密度之比）的反式相对论重联。我们发现，磁耗散的进行与加热的离子和康普顿冷却的电子之间的能量交换效率低下。因此，大多数电子在辐射下保持在康普顿平衡的低温下，因此热康普顿化不能达到从吸积黑洞观察到的光子能量keV。然而，磁重联有效地产生skeV光子，因为温和的相对论性的整体运动的等离子体链中形成的重联层。由等离子体团运动引起的康普顿化控制了辐射输出，并控制了辐射谱Epk的峰值。当σ = 1时，Epk为40 keV，当σ = 3时，Epk为100 keV.除了100 keV左右的X射线峰外，模拟还显示了由重连层的X点附近产生的非热电子群发射的非热MeV尾部。结果与吸积黑洞的典型硬态一致。特别地，我们发现天鹅座X-1的光谱很好地解释了电子-离子重联与σ π 3。
We perform 2D particle-in-cell simulations of magnetic reconnection in electron-ion plasmas subject to strong Compton cooling and calculate the X-ray spectra produced by this process. The simulations are performed for trans-relativistic reconnection with magnetization 1 ≤ σ ≤ 3 (defined as the ratio of magnetic tension to plasma rest-mass energy density), which is expected in the coronae of accretion discs around black holes. We find that magnetic dissipation proceeds with inefficient energy exchange between the heated ions and the Compton-cooled electrons. As a result, most electrons are kept at a low temperature in Compton equilibrium with radiation, and so thermal Comptonization cannot reach photon energieskeV observed from accreting black holes. Nevertheless, magnetic reconnection efficiently generateskeV photons because of mildly relativistic bulk motions of the plasmoid chain formed in the reconnection layer. Comptonization by the plasmoid motions dominates the radiative output and controls the peak of the radiation spectrumEpk. We findEpk∼ 40 keV for σ = 1 andEpk∼ 100 keV for σ = 3. In addition to the X-ray peak around 100 keV, the simulations show a non-thermal MeV tail emitted by a non-thermal electron population generated near X-points of the reconnection layer. The results are consistent with the typical hard state of accreting black holes. In particular, we find that the spectrum of Cygnus X-1 is well explained by electron-ion reconnection with σ ∼ 3.