Accretion-Induced Collapse of Neutron Stars in the Disks of Active Galactic Nuclei
Accretion-Induced Collapse of Neutron Stars in the Disks of Active Galactic Nuclei
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DOI：
10.3847/1538-4357/abfdb4
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
R. Perna;H. Tagawa;Z. Haiman;I. Bartos
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文献类型：
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作者：
R. Perna;H. Tagawa;Z. Haiman;I. Bartos
活动星系核（AGN）盘已成为恒星及其致密残余物演化的丰富环境。非常致密的介质有利于快速吸积，而扭矩和迁移陷阱则增强了双星的形成和合并。因此，预计会发生长伽马射线暴和短伽马射线暴。我们表明，活动星系核盘构成了另一个有趣现象的理想环境：中子星（NS）到黑洞（BH）的吸积引起的塌缩（AIC）。致密盘中的快速吸积会导致NS增长到超过其状态方程允许的最大质量的程度。一般相对论磁流体动力学模拟表明，如果 NS 在坍缩之前被微型盘包围，然后迅速吸积到 BH 上，和/或如果 NS 高度磁化，则在坍缩期间磁层重新连接时，预计会出现电磁特征。在这里，我们计算孤立 NS 和由 NS-NS 合并形成的（初始稳定的）NS 的 AIC 率及其在磁盘内的位置。我们发现全球 AIC 率为 ∼0.07–20 Gpc−3 yr−1，并且我们讨论了它们从密集磁盘环境中出现时的可观察前景和特征。
The disks of active galactic nuclei (AGNs) have emerged as a rich environment for the evolution of stars and their compact remnants. The very dense medium favors rapid accretion, while torques and migration traps enhance binary formation and mergers. Both long and short gamma-ray bursts are hence expected. We show that AGN disks constitute an ideal environment for another interesting phenomenon: the accretion-induced collapse (AIC) of neutron stars (NSs) to black holes (BHs). Rapid accretion in the dense disks can cause NSs to grow to the point of exceeding the maximum mass allowed by their equation of state. General relativistic magnetohydrodynamical simulations have shown that electromagnetic signatures are expected if the NS is surrounded by a minidisk prior to collapse, which then rapidly accretes onto the BH, and/or if the NS is highly magnetized, from reconnection of the magnetosphere during collapse. Here we compute the rates of AICs and their locations within the disks for both isolated NSs and for (initially stable) NSs formed from NS-NS mergers. We find that the global AIC rates are ∼0.07–20 Gpc−3 yr−1, and we discuss their observable prospects and signatures as they emerge from the dense disk environments.