Butler Satya P, Lima Alicia R, Baumgarte Thomas W, Shapiro Stuart L
Department of Physics and Astronomy, Bowdoin College, Brunswick, ME 04011, USA.
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Mon Not R Astron Soc. 2018 Jul;477(3):3694-3710. doi: 10.1093/mnras/sty834. Epub 2018 Apr 4.
The discovery of quasars at increasingly large cosmological redshifts may favour 'direct collapse' as the most promising evolutionary route to the formation of supermassive black holes. In this scenario, supermassive black holes form when their progenitors - supermassive stars - become unstable to gravitational collapse. For uniformly rotating stars supported by pure radiation pressure and spinning at the mass-shedding limit, the critical configuration at the onset of collapse is characterized by universal values of the dimensionless spin and radius parameters / and /, independent of mass . We consider perturbative effects of gas pressure, magnetic fields, dark matter, and dark energy on these parameters, and thereby determine the domain of validity of this universality. We obtain leading-order corrections for the critical parameters and establish their scaling with the relevant physical parameters. We compare two different approaches to approximate the effects of gas pressure, which plays the most important role, find identical results for the above dimensionless parameters, and also find good agreement with recent numerical results.
在越来越大的宇宙学红移处发现类星体，可能支持“直接坍缩”作为超大质量黑洞形成最有前景的演化途径。在这种情形下，超大质量黑洞在其前身——超大质量恒星——因引力坍缩变得不稳定时形成。对于由纯辐射压力支撑且以质量抛射极限旋转的均匀旋转恒星，坍缩开始时的临界构型由无量纲自旋和半径参数(J)和(R)的普适值表征，与质量无关。我们考虑气体压力、磁场、暗物质和暗能量对这些参数的微扰效应，从而确定这种普适性的有效范围。我们得到临界参数的一阶修正，并确定它们与相关物理参数的标度关系。我们比较两种不同的近似气体压力效应的方法，气体压力起最重要作用，对于上述无量纲参数得到相同结果，并且也与最近的数值结果吻合良好。
