Find the Gap: Black Hole Population Analysis with an Astrophysically Motivated Mass Function

Baxter, Eric J.; Croon, Djuna; McDermott, Samuel D.; Sakstein, Jeremy

Abstract

We introduce a novel black hole mass function that realistically models the physics of pair-instability supernovae with a minimal number of parameters. Applying this to all events in the LIGO-Virgo Gravitational-Wave Transient Catalog 2 (GWTC-2), we detect a peak at ${M}_{\mathrm{BHMG}}={46}_{-6}^{+17}\,{M}_{\odot }$. Repeating the analysis without the black holes from the event GW190521, we find this feature at MBHMG = 54 ± 6 M⊙. These results establish the edge of the anticipated "black hole mass gap" at a value compatible with the expectation from standard stellar structure theory. The mass gap manifests itself as a discontinuity in the mass function and is populated by a distinct, less-abundant population of higher-mass black holes. We find that the primary black hole population scales with power-law index −1.95 ± 0.51 (−1.97 ± 0.44) with (without) GW190521, consistent with models of star formation. Using Bayesian techniques, we establish that our mass function fits a new catalog of black hole masses approximately as well as pre-existing phenomenological mass functions. We also remark on the implications of these results for constraining or discovering new phenomena in nuclear and particle physics.

Citation

Baxter, E. J., Croon, D., McDermott, S. D., & Sakstein, J. (2021). Find the Gap: Black Hole Population Analysis with an Astrophysically Motivated Mass Function. Astrophysical Journal Letters, 916(2), Article L16. https://doi.org/10.3847/2041-8213/ac11fc

• Journal Article Type: Article
• Acceptance Date: Jul 7, 2021
• Online Publication Date: Jul 30, 2021
• Publication Date: 2021
• Deposit Date: Oct 14, 2021
• Publicly Available Date: Oct 14, 2021
• Journal: The Astrophysical Journal Letters
• Print ISSN: 2041-8205
• Electronic ISSN: 2041-8213
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 916
• Issue: 2
• Article Number: L16
• DOI: https://doi.org/10.3847/2041-8213/ac11fc
• Public URL: https://durham-repository.worktribe.com/output/1234980