2024/07/02 by Hernandez, Ignacio Magaña, Palmese, Antonella
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Astrophysical Phenomena (astro-ph.HE)
paper · doi:10.48550/arxiv.2407.02460
We analyze the confident binary black hole (BBH) detections from the third Gravitational-Wave Transient Catalog (GWTC-3) with an alternative mass population model in order to capture features in the mass distribution beyond the Powerlaw + Peak model. We find that the peak of a second power law characterizes the ∼ 30-35~ M_\odot bump, such that the data marginally prefers a mixture of two power laws for the mass distribution of binary components over a Powerlaw + Peak model with a Bayes Factor log10B of 0.24. This result may imply that the ∼ 30-35~ M_\odot feature represents the onset of a second population of BBH mergers (e.g. from a dynamical formation channel) rather than a specific mass feature over a broader distribution. When an additional Gaussian bump is allowed within our power law mixture model, we find a new feature in the BH mass spectrum at ∼65-70~M_\odot (log10B = 0.29 compared to Powerlaw + Peak). This new feature may be consistent with hierarchical mergers, and constitute ∼3% of the BBH population. This model also recovers a maximum mass of 58+32-14~M_\odot for the second power law, consistent with the onset of a pair-instability supernova mass gap.