Twin Peak: the dual nature of low-mass black hole binaries

by Jam Sadiq

Wednesday May 6, 2026, 1:00 PM → 2:00 PM Europe/Madrid

IFAE Seminar Room (In-person)

I will give a brief overview of recent work on the low-mass binary black hole (BBH) population observed in gravitational waves. A central challenge in this field is disentangling contributions from multiple formation channels, which overlap heavily in observable parameter space. I will explain the iterative KDE (Kernel Density Estimation) method and how we apply it to the latest LIGO-Virgo-KAGRA data through O4a to resolve two distinct sub-populations within the BBH merger rate peak at component masses of roughly 7-12 solar masses. One sub-population has a binary mass of ~16-20 solar masses with isotropically oriented spins of magnitude ~0.1, consistent with dynamical formation in dense stellar clusters. The other has a binary mass of ~18-22 solar masses with preferentially orbit-aligned spins of ~0.15, consistent with isolated binary evolution. I will discuss the implication of this results and possible future work with more observations of gravitational waves.