论文标题
在配对差距中黑洞的出色合并方案
The Stellar Merger Scenario for Black Holes in the Pair-instability Gap
论文作者
论文摘要
GW190521的最新检测激发了有关如何填充预测的黑洞配对质量间隙的想法。一个提出的方案是对两颗恒星的动态合并，在对稳定性方向下，形成一个小核心和一个超大尺寸的信封的恒星。我们通过详细的恒星演化计算探索了这种情况，从临时初始条件开始，在合并期间没有核心增长。我们概述了这种情况必须克服的主要挑战，尤其是在合并时，随后的进化和核心崩溃时保留足够多的质量的要求。我们发现，这些大规模合并产品可能是富含氦气的，并且将其剩余的大部分时间都花在Herzsprung-Russell图的地区，其中预计将具有类似于发光蓝色变量（LBV）爆发的包络不稳定性。忽略恒星后反应的质量损失量的能量估计表明，可以在低金属性下可以去除的总质量是。 1 m。这足够小，以至于在核心差异下，我们的模型保持了足够的质量，以形成黑洞，以类似于Ligo/pirgo检测到的新稳定性间隙。但是，合并时的质量损失和核心崩溃时中微子驱动的质量损失仍需要量化这些模型，以确认这种情况的可行性。
The recent detection of GW190521 stimulated ideas on how to populate the predicted black hole pair-instability mass gap. One proposed scenario is the dynamical merger of two stars below the pair instability regime forming a star with a small core and an over-sized envelope. We explore this scenario with detailed stellar evolution calculations, starting with ad-hoc initial conditions enforcing no core growth during the merger. We outline the main challenges this scenario has to overcome, in particular the requirement to retain enough of its mass at merger time, in the subsequent evolution, and at core-collapse. We found that these massive merger products are likely helium-rich, and spend most of their remaining lifetime within regions of the Herzsprung-Russell diagram where envelope instabilities akin to luminous blue variable (LBV) eruptions are expected. An energetic estimate of the amount of mass loss neglecting the back-reaction of the star suggests that the total amount of mass that can be removed at low metallicity is . 1 M . This is small enough that at core-collapse our models are retaining sufficient mass to form black holes in the pair-instability gap similar to the recent ones detected by LIGO/Virgo. However, mass loss at the time of merger and the neutrino-driven mass loss at core collapse still need to be quantified for these models in order to confirm the viability of this scenario.
