Abstract

Invited Talk - Plenary

Friday, 11 September 2026, 11:30   (MW-1801 / virtual plenum)

Black hole mergers: insights from hundreds of gravitational wave observations

Michela Mapelli
Heidelberg University

Eleven years after the first detection, the population of black hole mergers observed by LIGO and Virgo numbers several hundred events, with masses ranging from a few to approximately two hundred solar masses. The black hole mass function reveals structures that are increasingly sharply defined, and correlations with the spin parameters have begun to emerge. The merger rate density is now constrained to be ~25–50 Gpc⁻³ yr⁻¹ within the 90% credible interval. While its evolution with redshift appears broadly consistent with expectations for stellar-origin black holes, the actual value of the merger rate density is in tension with most numerical models. In my talk, I will show that this tension arises primarily from the isolated binary evolution channel. I will explore possible solutions, including the impact of natal kicks, mass transfer stability, and overly simplified core-collapse supernova models.