2024/11/11 by Gabriel Sasseville, Julie Hlavacek-Larrondo, Sasseville, Gabriel +13
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2411.07242
openalex publication_date 2024/11/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The strongest and most universal scaling relation between a supermassive black hole and its host galaxy is known as the M_\bullet-σ relation, where M_\bullet is the mass of the central black hole and σ is the stellar velocity dispersion of the host galaxy. This relation has been studied for decades and is crucial for estimating black hole masses of distant galaxies. However, recent studies suggest the potential absence of central black holes in some galaxies, and a significant portion of current data only provides upper limits for the mass. Here, we introduce a novel approach using a Bayesian hurdle model to analyze the M_\bullet-σ relation across 244 galaxies. This model integrates upper mass limits and the likelihood of hosting a central black hole, combining logistic regression for black hole hosting probability with a linear regression of mass on σ. From the logistic regression, we find that galaxies with a velocity dispersion of 11, 34 and 126 km/s have a 50%, 90% and 99% probability of hosting a central black hole, respectively. Furthermore, from the linear regression portion of the model, we find that M_\bullet ∝ σ5.8, which is significantly steeper than the slope reported in earlier studies. Our model also predicts a population of under-massive black holes (M_\bullet=10-105 M_\odot) in galaxies with σ\lesssim 127 km/s and over-massive black holes (M_\bullet ≥ 1.8 × 107) above this threshold. This reveals an unexpected abundance of galaxies with intermediate-mass and ultramassive black holes, accessible to next-generation telescopes like the Extremely Large Telescope.