论文标题
恒星进化中GW190521的形成：氢富含氢的信封，挖掘和$^{12} $ c（$α$，$γ$）$^{16} $ o对配对稳定的黑洞质量间隙的影响
Formation of GW190521 from stellar evolution: the impact of the hydrogen-rich envelope, dredge-up and $^{12}$C($α$, $γ$)$^{16}$O rate on the pair-instability black hole mass gap
论文作者
论文摘要
预计配对不稳定（pi）将在$ \ of {} 40-65 $ m $ _ \ odot $和$ \ od {} 120 $ m $ _ $ _ \ odot $之间打开黑洞（BHS）质谱的差距。当前，质量差距的存在受到GW190521的检测而受到挑战，主要组件质量为$ 85^{+21} _ { - 14} $ M $ _ {\ odot} $。在这里，我们研究了PI质量差距上的主要不确定性：$^{12} $ c（$α$，$γ$）$^{16} $ o反应速率和H-HICH信封崩溃。使用标准$^{12} $ c（$α$，$γ$）$^{16} $ o速率，如果我们允许在金属上$ z \ leq {} 0.0003 $的残留H-rich Inevelope倒塌，则质量间隙的下边缘可以是70 m $ _ \ odot $。采用Starlib数据库给出的不确定性，用于使用$^{12} $ C（$α$，$γ$）$^{16} $ o rates $ -1 \，σ$计算的型号带有$ m _ {\ rm zams}> 110 $ m $ _ \ odot $的星星可能会在核心氦气燃烧阶段经历深度的疏edge情节，从而从核心中提取了丰富信封的核心。由于He-core质量减少，$ m _ {\ rm zams} = 160 $ m $ _ \ odot $的星星可能会避免使用PI并产生150 m $ $ _ odot $的BH。在$ -2 \，{}σ$情况下，PI质量差距从92 m $ _ \ odot $到110 m $ _ \ odot $。最后，在使用$^{12} $ C（$α$，$γ$）$^{16} $ o $ -3 \，{}σ$计算的型号中，通过疏ledge效应完全消除了质量间隙。这种挖掘的开始对对流和混合的假定模型特别敏感。富含H的信封倒塌和低$^{12} $ C（$α$，$γ$）$^{16} $ o速率的综合效果可以导致与GW190521的主要成分一致的BHS的形成。
Pair-instability (PI) is expected to open a gap in the mass spectrum of black holes (BHs) between $\approx{}40-65$ M$_\odot$ and $\approx{}120$ M$_\odot$. The existence of the mass gap is currently being challenged by the detection of GW190521, with a primary component mass of $85^{+21}_{-14}$ M$_{\odot}$. Here, we investigate the main uncertainties on the PI mass gap: the $^{12}$C($α$, $γ$)$^{16}$O reaction rate and the H-rich envelope collapse. With the standard $^{12}$C($α$, $γ$)$^{16}$O rate, the lower edge of the mass gap can be 70 M$_\odot$ if we allow for the collapse of the residual H-rich envelope at metallicity $Z\leq{}0.0003$. Adopting the uncertainties given by the STARLIB database, for models computed with the $^{12}$C($α$, $γ$)$^{16}$O rate $-1\, σ$, we find that the PI mass gap ranges between $\approx{}80$ M$_\odot$ and $\approx{}150$ M$_\odot$. Stars with $M_{\rm ZAMS}>110$ M$_\odot$ may experience a deep dredge-up episode during the core helium-burning phase, that extracts matter from the core enriching the envelope. As a consequence of the He-core mass reduction, a star with $M_{\rm ZAMS} =160$ M$_\odot$ may avoid the PI and produce a BH of 150 M$_\odot$. In the $-2\,{}σ$ case, the PI mass gap ranges from 92 M$_\odot$ to 110 M$_\odot$. Finally, in models computed with $^{12}$C($α$, $γ$)$^{16}$O $-3\,{}σ$, the mass gap is completely removed by the dredge-up effect. The onset of this dredge-up is particularly sensitive to the assumed model for convection and mixing. The combined effect of H-rich envelope collapse and low $^{12}$C($α$, $γ$)$^{16}$O rate can lead to the formation of BHs with masses consistent with the primary component of GW190521.
