Is there an excess of black holes around $20 M_{\odot}$? Optimising the complexity of population models with the use of reversible jump MCMC

Understand

Some analyses of the third gravitational wave catalogue released by the LIGO-Virgo-KAGRA collaboration (LVK) suggest an excess of black holes around $15-20 M_{\odot}$.

• In order to investigate this feature, we introduce two flexible population models, a semi-parametric one and a non-parametric one.
• Both make use of reversible jump Markov chain Monte-Carlo to optimise their complexity.
• We also illustrate how the latter can be used to efficiently perform model selection.