主讲人单位 (Speaker's Institute): 意大利帕多瓦大学

邀请人 (Invited by): 王龙、 黄志琦

时间 (Time): 星期日,2022/05/26-16:30 to 17:30

地点 (Location): Zoom/珠海校区天琴中心3416会议室

摘要 (Abstract): 

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, others partially overlap with the lower mass gap (~2-5 Msun). On the one hand, population models of massive binary stars predict black hole masses in the range ~ 3 - 50 Msun, with nearly aligned spins, but are affected by large uncertainties. On the other hand, dynamics of dense stellar clusters can trigger the formation of binary black holes with largely misaligned spins, 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. Furthermore, the redshift evolution of binary black holes is one of the key features to understand their formation, in preparation for next-generation gravitational-wave detectors.

主讲人简介 (Speaker's CV): 

Michela Mapelli obtained her PhD in Astrophysics in 2006, from SISSA (Trieste). In 2011, after a postdoctoral fellowship at the University of Zurich, she became tenured staff researcher at the Italian National Institute for Astrophysics (INAF). In 2017, she became a fixed-term full professor and chair of the Extragalactic Astrophysics Group at the University of Innsbruck. She is now associate professor at the University of Padova and visiting professor at the Gran Sasso Science Institute (GSSI), in Italy. During her career, she obtained several prizes for her research, including the MERAC prize (2015) for the best early-career researcher in Theoretical Astrophysics and an ERC consolidator grant (2017). Michela is a member of the Virgo collaboration and one of the chairs of Division 3 of the Einstein Telescope's Observation Science Board. Her research focuses on the formation channels of binary black holes and neutron stars.