CENTRAL ENGINE OF LATE-TIME X-RAY FLARES WITH INTERNAL ORIGIN
CENTRAL ENGINE OF LATE-TIME X-RAY FLARES WITH INTERNAL ORIGIN
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DOI：
10.3847/0004-637x/832/2/161
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
Hui-Jun Mu;Weimin Gu;S. Hou;Tong Liu;D. Lin;Tuan Yi;E. Liang;Ju-fu Lu
中科院分区：
文献类型：
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作者：
Hui-Jun Mu;Weimin Gu;S. Hou;Tong Liu;D. Lin;Tuan Yi;E. Liang;Ju-fu Lu
本文对7个具有峰值时间的极晚期X射线耀斑样本进行了研究，其中两个耀斑可以确定为中心引擎的晚期活动。本文的主要目的是基于内源假设来研究这种晚期耀斑的形成机制。在超吸积黑洞（BH）的情况下，我们研究了两种众所周知的机制作为中央引擎为这种X射线耀斑提供动力的可能性，即，中微子-反中微子湮灭和Blandford-Znajek（BZ）过程。结果表明，湮灭光度远低于观测值。因此，湮灭机制不能解释这种晚期耀斑。对于BZ过程，如果考虑流出的作用，视界附近的流入质量速率将非常低，使得磁场可能太弱而不能为观测到的X射线耀斑提供能量。因此，我们认为，对于晚期耀斑与内部起源，中央引擎是不可能与黑洞。相反，一个快速旋转的中子星星和强大的双极磁场可能是造成这种耀斑的原因。
This work focuses on a sample of seven extremely late-time X-ray flares with peak time , among which two flares can be confirmed as the late-time activity of central engine. The main purpose is to investigate the mechanism of such late-time flares based on the internal origin assumption. In the hyper-accreting black hole (BH) scenario, we study the possibility of two well-known mechanisms acting as the central engine to power such X-ray flares, i.e., the neutrino–antineutrino annihilation and the Blandford–Znajek (BZ) process. Our results show that the annihilation luminosity is far below the observational data. Thus, the annihilation mechanism cannot account for such late-time flares. For the BZ process, if the role of outflows is taken into consideration, the inflow mass rate near the horizon will be quite low such that the magnetic field will probably be too weak to power the observed X-ray flares. We therefore argue that, for the late-time flares with internal origin, the central engine is unlikely to be associated with BHs. On the contrary, a fast rotating neutron star with strong bipolar magnetic fields may be responsible for such flares.