The Black Hole Mass Function Across Cosmic Times I. Stellar Black Holes and Light Seed Distribution

Understand

This is the first paper in a series aimed at modeling the black hole (BH) mass function, from the stellar to the intermediate to the (super)massive regime.

• In the present work we focus on stellar BHs and provide an ab-initio computation of their mass function across cosmic times.
• Specifically, we exploit the state-of-the-art stellar and binary evolutionary code \texttt{SEVN}, and couple its outputs with redshift-dependent galaxy statistics and empirical scaling relations involving galaxy metallicity, star-formation rate and stellar mass.
• The resulting relic mass function ${\rm d}N/{\rm d}V{\rm d}\log m_\bullet$ as a function of the BH mass $m_\bullet$ features a rather flat shape up to $m_\bullet\approx 50\, M_\odot$ and then a log-normal decline for larger masses, while its overall normalization at a given mass increases with decreasing redshift.