Deciphering the properties of the central engine in GRB collapsars
Deciphering the properties of the central engine in GRB collapsars
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DOI：
10.1093/mnras/staa1695
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发表时间：
2020-06
影响因子：
4.8
通讯作者：
M. Petropoulou;P. Beniamini;G. Vasilopoulos;D. Giannios;R. Barniol Duran-R.-Barniol Duran-2126751779
中科院分区：
文献类型：
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作者：
M. Petropoulou;P. Beniamini;G. Vasilopoulos;D. Giannios;R. Barniol Duran-R.-Barniol Duran-2126751779
长伽玛射线暴（GRB）的中心引擎被认为是由大质量恒星的核心坍缩产生的紧凑物体，但其确切性质（黑洞或毫秒磁星）仍然存在争议。虽然伽玛射线暴的中央引擎是隐藏的直接观察，它的属性可能会印在伴随的电磁信号。我们的目标是破译中央引擎的通用属性，这与尼尔·盖尔斯·斯威夫特天文台上的突发警报望远镜（BAT）探测到的长GRB的及时观测是一致的。采用一个通用的中央引擎模型，其中引擎的功率和活动的时间尺度是相互独立的，我们进行Monte Carlo模拟的长伽玛暴的喷流，成功地从星星突破。我们的模拟考虑了喷气爆发时间尺度对发动机光度的依赖性和探测器通量阈值的影响。模拟的可探测的伽玛射线爆发的二维（2D）分布与伽玛射线的亮度与持续时间平面与观察到的一个描述中央引擎的参数值的范围是一致的。模拟的GRBs的固有2D分布在较低的伽马射线光度和较长的持续时间比观察到的峰值，预测，可以在未来测试更灵敏的探测器。黑洞吸积体的功率和活动时间分别由通过祖星星和恒星结构的大尺度磁通量决定，这与我们模型推断的中心引擎的性质是相容的。
The central engine in long gamma-ray bursts (GRBs) is thought to be a compact object produced by the core collapse of massive stars, but its exact nature (black hole or millisecond magnetar) is still debatable. Although the central engine of GRB collapsars is hidden to direct observation, its properties may be imprinted on the accompanying electromagnetic signals. We aim to decipher the generic properties of central engines that are consistent with prompt observations of long GRBs detected by the Burst Alert Telescope (BAT) on board the Neil Gehrels Swift Observatory. Adopting a generic model for the central engine, in which the engine power and activity time-scale are independent of each other, we perform Monte Carlo simulations of long GRBs produced by jets that successfully breakout from the star. Our simulations consider the dependence of the jet breakout time-scale on the engine luminosity and the effects of the detector’s flux threshold. The two-dimensional (2D) distribution of simulated detectable bursts in the gamma-ray luminosity versus gamma-ray duration plane is consistent with the observed one for a range of parameter values describing the central engine. The intrinsic 2D distribution of simulated collapsar GRBs peaks at lower gamma-ray luminosities and longer durations than the observed one, a prediction that can be tested in the future with more sensitive detectors. Black hole accretors, whose power and activity time are set by the large-scale magnetic flux through the progenitor star and stellar structure, respectively, are compatible with the properties of the central engine inferred by our model.