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arXiv 2312.02269astro-ph.HE
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超快致密双星并合

Ultrafast compact binary mergers

Paz Beniamini, Tsvi Piran

AI总结:

本文提出第二次坍缩中的踢动可使致密双星并合时间分布呈 $t^{2/7}$ 规律,产生短至 10 Myr 甚至小于 10 kyr 的超快并合,并解释部分短伽马射线暴的起源。

摘要:

由引力波(GWs)引起的轨道衰减持续时间往往是恒星形成到并合这一演化阶段的瓶颈。我们在此表明,在第二次坍缩期间赋予新诞生致密天体的踢动通常会导致引力波并合时间分布表现为在短时标下 $dN/d\log t \propto t^{2/7}$,从而产生超快并合。也就是说,以这种方式形成的中子星双星中有不可忽略的一部分将在短至 10 Myr 的时间尺度上并合,还有一小部分甚至会在小于 10 kyr 的时间尺度上并合。这些结果可应用于不同类型的致密双星。我们在此讨论其对双中子星并合的影响。这些影响包括独特的短伽马射线暴(GRBs)、偏心且不对准的并合、极早期宇宙和恒星形成活跃区域中的 $r$-过程增丰,以及可能的射电前兆。有趣的是,我们得出结论:在迄今探测到的数百个短 GRB 中,必定有少数是通过这种超快通道形成的。

英文摘要:

The duration of orbital decay induced by gravitational waves (GWs) is often the bottleneck of the evolutionary phases going from star formation to a merger. We show here that kicks imparted to the newly born compact object during the second collapse generically result in a GW merger time distribution behaving like $dN/d\log t \propto t^{2/7}$ at short durations, leading to ultrafast mergers. Namely, a nonnegligible fraction of neutron star binaries, formed in this way, will merge on a time scale as short as 10 Myr, and a small fraction will merge even on a time scale less than 10 kyr. The results can be applied to different types of compact binaries. We discuss here the implications for binary neutron star mergers. These include unique short gamma-ray bursts (GRBs), eccentric and misaligned mergers, $r$-process enrichment in the very early Universe and in highly star-forming regions, and possible radio precursors. Interestingly, we conclude that among the few hundred short GRBs detected so far, a few must have formed via this ultrafast channel.

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。

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