A new bump in the night: evidence of a new feature in the binary black hole mass distribution at $70~M_{odot}$ from gravitational-wave observations
Ignacio Maga~na Hernandez, Antonella Palmese
arXiv:2407.02460v2 Announce Type: replace
Abstract: 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 $sim 30-35~ M_odot$ 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 $log_{10}mathcal{B}$ of 0.24. This result may imply that the $sim 30-35~ M_odot$ 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 $sim65-70~M_odot$ ($log_{10}mathcal{B}$ = 0.29 compared to Powerlaw + Peak). This new feature may be consistent with hierarchical mergers, and constitute $sim3%$ 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.arXiv:2407.02460v2 Announce Type: replace
Abstract: 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 $sim 30-35~ M_odot$ 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 $log_{10}mathcal{B}$ of 0.24. This result may imply that the $sim 30-35~ M_odot$ 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 $sim65-70~M_odot$ ($log_{10}mathcal{B}$ = 0.29 compared to Powerlaw + Peak). This new feature may be consistent with hierarchical mergers, and constitute $sim3%$ 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.