Intermediate-mass Black Holes from High Massive-star Binary Fractions in Young Star Clusters
Intermediate-mass Black Holes from High Massive-star Binary Fractions in Young Star Clusters
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DOI：
10.3847/2041-8213/abdf5b
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发表时间：
2020-12
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影响因子：
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通讯作者：
E. Gonz'alez;K. Kremer;S. Chatterjee;G. Fragione;C. Rodriguez;Newlin C. Weatherford;Claire S. Ye;F. Rasio
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文献类型：
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作者：
E. Gonz'alez;K. Kremer;S. Chatterjee;G. Fragione;C. Rodriguez;Newlin C. Weatherford;Claire S. Ye;F. Rasio
在密集的星团中形成的黑洞，动态相互作用频繁，可能与那些通过孤立的恒星演化形成的黑洞具有根本不同的特性。单星演化的理论模型预测黑洞质量谱中大约40-120 M⊙的间隙是由（脉动）对不稳定超新星引起的。在最近的LIGO/Virgo事件GW190521的激励下，我们研究了质量在这个“上质量间隙”之内或超过这个“上质量间隙”的黑洞是否可以通过双星中大质量恒星的强相互作用在年轻的星团中动态形成。我们使用CMC星团动力学代码进行了一组n体模拟，以研究高质量双星分数对最大质量恒星及其残余物的形成和碰撞历史的影响。我们发现，在大质量恒星中具有低金属丰度和高二元分数的典型年轻星团可以在高质量间隙中形成几个黑洞，并且通常至少形成一个中等质量黑洞。这些结果提供了强有力的证据，证明年轻星团中的动态相互作用自然会导致更大质量黑洞残留物的形成。
Black holes formed in dense star clusters, where dynamical interactions are frequent, may have fundamentally different properties than those formed through isolated stellar evolution. Theoretical models for single-star evolution predict a gap in the black hole mass spectrum from roughly 40–120 M⊙ caused by (pulsational) pair-instability supernovae. Motivated by the recent LIGO/Virgo event GW190521, we investigate whether black holes with masses within or in excess of this “upper-mass gap” can be formed dynamically in young star clusters through strong interactions of massive stars in binaries. We perform a set of N-body simulations using the CMC cluster-dynamics code to study the effects of the high-mass binary fraction on the formation and collision histories of the most massive stars and their remnants. We find that typical young star clusters with low metallicities and high binary fractions in massive stars can form several black holes in the upper-mass gap and often form at least one intermediate-mass black hole. These results provide strong evidence that dynamical interactions in young star clusters naturally lead to the formation of more massive black hole remnants.