Michela Mapelli
Dipt. Astron., Univ. Padova (Padoue, Italie)
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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| « The challenge of binary black holes: mass gap and redshift evolution » |
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Michela Mapelli |
| The results of LIGO and Virgo open a new perspective for the study of binary black holes: we now know of nearly one hundred candidate systems. Because of the new data, theoretical and numerical models of binary black hole formation face a serious challenge: several LIGO-Virgo black holes have mass in the upper mass gap (~60-120 Msun) predicted by pair-instability theory. On the one hand, population models of massive binary stars predict black hole masses in the range ~ 3 - 50 Msun, but are affected by large uncertainties. On the other hand, dynamics of dense stellar clusters can trigger the formation of unusually massive binary black holes, and even fill the pair instability mass gap. In this talk, I will present new theoretical models of the formation of massive (>60 Msun) black holes via multiple stellar collisions and hierarchical mergers of low-mass black holes in dense star clusters. Metal-free and metal-poor stars can largely contribute to the formation of these massive binary black holes in the high-redshift Universe: the next-generation gravitational-wave detectors will probe binary black hole mergers out to a redshift of several tens, unraveling this new population. |
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vendredi 14 avril 2023 - 11:00 Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |