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.

在密集的星团中形成的黑洞，经常发生动力学相互作用，其性质可能与通过孤立的恒星演化形成的性质完全不同。单星演化理论模型预测从大致40-120在黑洞质谱的间隙中号 _⊙引起（速度脉冲）对不稳定性超新星。受最近的LIGO /处女座事件GW190521的激发，我们研究了质量是否在“超大质量间隙”之内或之外的黑洞是否可以通过双星中大质量恒星的强烈相互作用而在年轻恒星团中动态形成。我们使用CMC执行了一组N体模拟聚类动力学代码研究高质量双星分数对最大质量恒星及其残骸的形成和碰撞历史的影响。我们发现，典型的年轻金属星团在大质量恒星中具有较低的金属含量和较高的二元分数，它们可以在上部质量间隙中形成多个黑洞，并经常形成至少一个中等质量黑洞。这些结果提供了有力的证据，表明年轻恒星团中的动力学相互作用自然会导致形成更大质量的黑洞残余。