标题： 大质量恒星黑洞双星的形成与引力波探测 显示英文标题

标题： The Formation and Gravitational-Wave Detection of Massive Stellar Black-Hole Binaries

摘要： 如果存在由两个100太阳质量黑洞组成的双星系统，它们将作为极其强大的引力波源，可被先进的LIGO/Virgo地面探测器探测到红移z=2的范围。 关于大质量恒星演化的巨大不确定性使得无法对这些大质量黑洞合并的速率做出确定性的预测。 我们表明，每年高达数百次的探测率，或者甚至完全没有探测到的情况，都是可能的。 人们曾认为产生这些大质量双星的唯一途径是通过密集恒星系统中的动力学相互作用。 最近在大麦哲伦星系R136区域发现了几颗质量超过150太阳质量的恒星，这一发现挑战了这一观点。 当前模型预测，当这类质量的恒星离开主序星阶段时，它们的膨胀不足以使共同包层演化有效地减少轨道分离度。 resulting black-hole--black-hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black-hole--black-hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars. 显示英文摘要

摘要： If binaries consisting of two 100 Msun black holes exist they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z=2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by the recent discovery of several stars with mass above 150 Msun in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black-hole--black-hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black-hole--black-hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.