arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.4379astro-ph.HE
收藏

超大质量恒星坍缩产生的硬X射线爆发

Hard X-ray Bursts from Collapse of the Super Massive Stars

Maxim V. Barkov

摘要:

宇宙中最早的恒星质量可能非常大,可达$10^6M_\odot$。它们会留下巨大的黑洞,这些黑洞可以作为活动星系核的超大质量黑洞的种子。考虑到预期的快速旋转,这样的恒星将以超大质量的双星结束生命,并驱动强大的磁主导喷流。本文研究了观测到与正常类星体相关的长伽马射线暴类似的高能辐射暴的可能性。我们表明,在超巨星坍缩过程中,Blandford-Znajek机制可以产生强大的喷流作为几个$\times10^{51}$尔格/秒,并释放高达$10^{56}$尔格的黑洞旋转能量。由于更高的内在时间尺度和更高的红移,爆发的初始亮相可以持续大约$10^5$秒,而中央引擎将保持活跃大约10天。由于红移很高,爆发的光谱预计会很柔和,光谱能量分布在60 keV左右达到峰值。其峰值总通量密度比较低,$\times 10^{-7}erg\, cm^{-2} s^{-1}$很少,但并不令人望而却步。这类事件的发生时间应晚于$^{-1}$的0.03年,观测需要长期计划,可在将来进行。

英文摘要:

The very first stars in the Universe can be very massive, up to $10^6M_\odot$. They would leave behind massive black holes that could act as seeds for growing super massive black holes of active galactic nuclei. Given the anticipated fast rotation such stars would end their live as super massive collapsars and drive powerful magnetically-dominated jets. In this paper we investigate the possibility of observing the bursts of high-energy emission similar to the Long Gamma Ray Bursts associated with normal collapsars. We show that during the collapse of supercollapsars, the Blandford-Znajek mechanism can produce jets as powerful as few$\times10^{51}$erg/s and release up to $10^{56}$erg of the black hole rotational energy. Due to the higher intrinsic time scale and higher redshift the initial bright phase of the burst can last for about $10^5$ seconds whereas the central engine would remain active for about 10 days. Due to the high redshift the burst spectrum is expected to be soft, with the spectral energy distribution peaking at around 60keV. The peak total flux density is relatively low, few$\times 10^{-7}erg\, cm^{-2} s^{-1}$, but not prohibitive. The such events should be rear 0.03 year$^{-1}$, the observations needs long term program and could be done in future.

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。

↑