Polluting the pair-instability mass gap for binary black holes through super-Eddington accretion in isolated binaries

Understand

The theory for single stellar evolution predicts a gap in the mass distribution of black holes (BHs) between approximately 45-130M$_{\odot}$, the so-called "pair-instability mass gap".

• We examine whether BHs can pollute the gap after accreting from a stellar companion.
• To this end, we simulate the evolution of isolated binaries using a population synthesis code, where we allow for super-Eddington accretion.
• Under our most extreme assumptions, we find that at most about 2% of all merging binary BH systems contains a BH with a mass in the pair-instability mass gap, and we find that less than 0.5% of the merging systems has a total mass larger than 90M$_{\odot}$.