Good things always come in 3s: trimodality in the binary black-hole chirp-mass distribution supports bimodal black-hole formation
Recent advancements in stellar evolution theory suggest that key properties of the core structure of stars prior to core-collapse are bimodal functions of the intial mass, that this bimodality is only weakly affected by mass transfer interactions, and that the resulting newborn black hole population has a bimodal mass distribution. Building on this, I show how this bimodal black hole mass structure can be validated with recent observations of merging binary black holes, which show a corresponding trimodal structure in the chirp mass. Moreover, the observed relative heights of the three chirp mass peaks are sensitive to uncertain physics in the interactions of the binary, providing constraints on binary evolution.