arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2303.12935astro-ph.HEastro-ph.COastro-ph.SR
收藏

GRB 191019A:来自活动星系核盘的一个伪装的短伽马射线暴

GRB 191019A: a short gamma-ray burst in disguise from the disk of an active galactic nucleus

Davide Lazzati, Rosalba Perna, Benjamin Gompertz, Andrew Levan

AI总结:

研究提出长暴GRB 191019A实为活动星系核盘内致密天体并合产生的短暴,其辐射因致密介质相互作用被拉长,双峰光变曲线特征支持该模型。

摘要:

长伽马射线暴和短伽马射线暴(GRBs)通常以约2秒的持续时间为界进行区分,它们分别与不同的前身星相关:大质量恒星的坍缩和两个致密天体的并合。GRB 191019A是一个长GRB($T_{90}\sim64$ s)。尽管红移相对较小(z=0.248)并进行了HST后续观测,但并未探测到伴随的超新星。此外,其宿主星系没有显著的恒星形成活动。我们提出GRB 191019A是由双致密天体并合产生的,其瞬时辐射因与致密外部介质的相互作用而在时间上被拉长。如果暴前身星位于活动星系核的盘中,就会出现这种情况,该暴在宿主星系中心附近的定位也支持了这一点。我们表明,GRB 191019A的光变曲线可以很好地用一个内禀持续时间为t=1.1 s、能量为$E_{\rm{iso}}=10^{51}$ erg、中等偏离轴向观测,并且在密度为$10^7-10^8$ cm$^{-3}$的介质中爆炸的暴来建模。双峰光变曲线带有高密度介质中GRBs的典型预测特征,其中第一个峰由光球产生,第二个峰由发生在内部激波发生之前的反向激波重叠产生。这将使GRB 191019A成为首个在吸积盘内被证实的恒星爆炸,对吸积流中恒星的形成与演化以及引力波源族群具有重要意义。

英文摘要:

Long and short gamma-ray bursts (GRBs), canonically separated at around 2 seconds duration, are associated with different progenitors: the collapse of a massive star and the merger of two compact objects, respectively. GRB 191019A was a long GRB ($T_{90}\sim64$ s). Despite the relatively small redshift z=0.248 and HST followup observations, an accompanying supernova was not detected. In addition, the host galaxy did not have significant star formation activity. Here we propose that GRB 191019A was produced by a binary compact merger, whose prompt emission was stretched in time by the interaction with a dense external medium. This would be expected if the burst progenitor was located in the disk of an active galactic nucleus, as supported by the burst localization close to the center of its host galaxy. We show that the light curve of GRB 191019A can be well modeled by a burst of intrinsic duration t=1.1 s and of energy $E_{\rm{iso}}=10^{51}$ erg seen moderately off-axis, exploding in a medium of density $10^7-10^8$ cm$^{-3}$. The double-peaked light curve carries the telltale features predicted for GRBs in high-density media, where the first peak is produced by the photosphere, and the second by the overlap of reverse shocks that take place before the internal shocks could happen. This would make GRB 191019A the first confirmed stellar explosion from within an accretion disk, with important implications for the formation and evolution of stars in accretion flows and for gravitational waves source populations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑