Resonant Shattering Flares in Black Hole-Neutron Star and Binary Neutron Star Mergers
Resonant Shattering Flares in Black Hole-Neutron Star and Binary Neutron Star Mergers
复制标题
黑洞-中子星和双中子星合并中的共振粉碎耀斑
DOI：
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发表时间：
2021
影响因子：
4.8
通讯作者：
W. Newton
中科院分区：
文献类型：
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作者：
D. Neill;D. Tsang;H. van Eerten;G. Ryan;W. Newton
共振破碎耀斑（RSFs）是伽马射线的爆发，预计是由中子星星（NS）在双星螺旋期间的潮汐共振触发的。它们强烈依赖于NS表面的磁场强度。通过模拟这些耀斑是在共振窗口期间发射的多个碰撞相对论壳层的结果，我们发现瞬发的非热伽马射线发射可能具有高达几× 1048 erg s-1的光度，并且可以产生宽带余辉。我们使用BPASS人口合成代码计算可检测RSFs的预期速率，并对合并前表面磁场强度的演变有不同的假设。我们发现，可检测的RSFs的速率为每年10.0001 -5 BHNS合并和每年10.0005 -25 NSNS合并，与表面场衰减相对应的下限与磁热演化在纯地壳场一致，而上限是系统具有较长寿命的表面磁场的磁通冻结到超导核心的支持。如果一些观测到的SGRB前体耀斑确实是RSF，这表明中子星星人口的一部分存在一个寿命较长的表面场，我们可以预期RSF是最常见的可检测的EM对应GW检测BHNS合并。在GRB 170817 A之前未检测到RSF提供了Bsurf 1013.5G的祖NS磁场的上限。
Resonant Shattering flares (RSFs) are bursts of gamma-rays expected to be triggered by tidal resonance of a neutron star (NS) during binary inspiral. They are strongly dependent on the magnetic field strength at the surface of the NS. By modelling these flares as being the result of multiple colliding relativistic shells launched during the resonance window, we find that the prompt non-thermal gamma-ray emission may have luminosity up to a few × 1048erg s−1, and that a broad-band afterglow could be produced. We compute the expected rates of detectable RSFs using the BPASS population synthesis code, with different assumptions about the evolution of surface magnetic field strengths before merger. We find the rate of detectable RSFs to be ∼0.0001–5 per year for BHNS mergers and ∼0.0005–25 per year for NSNS mergers, with the lower bound corresponding to surface-field decay consistent with magneto-thermal evolution in purely crustal fields, while the upper bounds are for systems which have longer-lived surface magnetic fields supported by flux frozen into the superconducting core. If some of the observed SGRB precursor flares are indeed RSFs, this suggests the presence of a longer-lived surface field for some fraction of the neutron star population, and that we could expect RSFs to be the most common detectable EM counterpart to GW detections of BHNS mergers. The non-detection of a RSF prior to GRB170817A provides an upper bound on the magnetic fields of the progenitor NSs of Bsurf ∼ 1013.5G.