Black hole discharge: Very-high-energy gamma rays from black hole-neutron star mergers
Black hole discharge: Very-high-energy gamma rays from black hole-neutron star mergers
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DOI：
10.1103/physrevd.100.043025
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发表时间：
2019-05
影响因子：
5
通讯作者：
Z. Pan;Huan Yang
中科院分区：
文献类型：
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作者：
Z. Pan;Huan Yang
当质量比大于$\sim 5$（取决于黑洞的自旋和星星半径）时，黑洞与中子星星在最后的坍缩阶段不会发生星星破裂.在螺旋上升的后期，黑洞很可能是带电的，因为它穿过了中子星星携带的磁场，在合并后留下了一个暂时带电的黑洞。残余黑洞的不稳定带电状态通过与周围的等离子体和光子相互作用而迅速中和，我们通过数值求解非自旋BH背景下的1+1形式的Boltzmann方程组来研究第一原理。由此产生的基本情况如下。电子和正电子在BH电场中被加速，然后通过康普顿散射将能量损失给周围的软光子;更多的电子和正电子将通过硬光子与软光子碰撞或通过强电磁场中的施温格过程产生。当带电黑洞吸积足够多的相反电荷并被中和时，级联停止。我们发现总电能的$\sim 10\%$（取决于软光子能量和数密度）在时间间隔$\sim 1$ ms内被极高能量（$>50$ GeV，MAGIC望远镜的低能探测阈值）的伽马射线携带到无穷大，其谱近似为幂律，谱指数$\sim-2. 3 $。我们希望放电图片是真实的自旋带电BH以及。
With mass ratio larger than $\sim 5$ (which depends on the black hole spin and the star radius), star disruption is not expected for a black hole merging with a neutron star during the final plunge phase. In the late inspiral stage, the black hole is likely charged as it cuts through the magnetic field carried by the neutron star, leaving a temporarily charged black hole after merger. The unstable charged state of the remnant black hole rapidly neutralizes by interacting with the surrounding plasma and photons, which we investigate in first principle by numerically solving a coupled set of Boltzmann equations of 1+1 form for non-spinning BH background. The resulting basic picture is as follows. Electrons and positrons are accelerated in the BH electric field, which then lose energy to surrounding soft photons via Compton scattering; more electrons and positrons will be created from pair production as the hard photons colliding with soft photons, or through the Schwinger process in strong electromagnetic fields. The cascade stops when the charged black hole accretes enough opposite charges and becomes neutralized. We find that $\sim 10\%$ (which depends on the soft photon energy and number density) of the total electric energy is carried away to infinity in a time interval $\sim 1$ ms by very-high-energy ($>50$ GeV, the low energy detection threshold of the MAGIC telescope) gamma rays whose spectrum is approximately a power law with spectral index $\sim -2.3$. We expect the discharge picture to be true for spinning charged BHs as well.