Today, Michela Mapelli gave a webinar on “Binary compact objects across cosmic time” @ ESO (webinars replace ESO lunch talks during the covid lock-down). Here below, you can read the abstract, and you can find the link to the slides
The first direct detection of gravitational waves has confirmed the existence of binary black holes and opens a new window on the study of binary compact objects. In this talk, I will discuss the main astrophysical formation channels of binary compact objects in light of LIGO-Virgo data. On the one hand, models of stellar evolution and pair instability supernovae suggest a gap in the mass spectrum of black holes between ~60 and ~120 Msun. The boundaries of this gap depend on stellar rotation and on the efficiency of envelope removal. On the other hand, extreme dynamical processes in dense star clusters can fill the mass gap, via multiple stellar collisions and dynamical exchanges. Moreover, stellar dynamics enhances the formation of black hole – neutron star systems with extreme (<1:10) mass ratios. Based on a data-driven model, I will discuss the merger history of dynamical versus isolated binary compact objects across cosmic time, and its dependence on the cosmic star formation rate and on the stellar metallicity. Finally, I will show that the merger rate per galaxy mostly depends on the total stellar mass and on the star formation rate.
“Unofficial” recording at https://drive.google.com/open?id=1PndE3PybiFebv6bufPum9eFZClShPMWQ