Today we go deep into the perilous world of binary population synthesis! Using Nicola’s code MOBSE, our master student Maciej has implemented some new prescriptions for how supernovae explode and produce compact objects. In practice, we use the compactness (that’s mass over radius) of the stellar core before the explosion to decide if that specific star will form a neutron star or a black hole. This now needs to be compared carefully with gravitational-wave data, but we suggest that there are two key signatures one should look for: the lowest black hole masses and the relative merger rates between black holes and neutron stars.

Maciej Dabrowny, Nicola Giacobbo, Davide Gerosa.
Rendiconti Lincei. Scienze Fisiche e Naturali 32 (2021) 665–673.
arXiv:2106.12541  [astro-ph.HE].