Faculty Mentor: Ben Bromley (Physics & Astronomy, University of Utah)

The origin and growth of supermassive black holes (SMBHs) remain fundamental questions in astrophysics, with the underlying mechanisms still poorly constrained by observational data. One plausible growth channel, with evidence from tidal disruption events that occur when stars stray within their tidal radius of a SMBH, is stellar accretion. To investigate this possibility, we examine a binary capture mechanism as a means of facilitating stellar accretion, and assess the contribution to SMBH growth. Utilizing the model presented by Bromley et. al (2012), we develop a computational framework to simulate the growth of SMBHs across a range of galactic environments. This approach enables a systematic exploration of how stellar accretion may drive SMBH mass evolution under varying galactic conditions. In a data set of over 90 galaxies from Hannah et. al (2023), we identify two SMBHs for which stellar accretion may be a driver of recent black hole growth. Closer to home, a recent analysis of observed hypervelocity stars from the Large Magellanic Cloud (LMC) implicates binary interactions with a massive black hole (Han et. al, (2025). Every hypervelocity star produced in this way leaves a bound partner that may be accreted by the black hole. This evidence bolsters our own conclusions that the LMC’s black hole is presently growing through the accretion of captured stars.

Bibliography

Bromley, B. C., Kenyon, S. J., Geller, M. J., & Brown, W. R. (2012) Binary Disruption of Massive Black Holes: Hypervelocity Stars, S Stars and Tidal Disruption Events, The Astrophysical Journal, 749, L42, doi: 10.1088/2041-8205/749/2/L42

Jiwon, JH., El-Badry, K., Lucchini, S., Hernquist, L., Brown, W., Garavito-Camargo, N., Conroy, C., & Sara, R.. (2025) Hypervelocity Stars Trace a Supermassive Black Hole in the Large Magellanic Cloud, arXiv e-prints, arXiv:2502.00102, doi: 10.48550/arXiv.2502.00102

Hannah, C. H., Seth, A. C., Stone, N. C., & van Velzen, S. (2024), Counting the Unseen. I. Nuclear Density Scaling Relations for Nucleated Galaxies, The American Astronomical Society, AJ, 168, 137, doi: 10.3847/1538-3881/ad630a

Hills, J. Hyper-velocity and tidal stars from binaries disrupted by a massive Galactic black hole. Nature 331, 687–689 (1988). https://doi.org/10.1038/331687a0