Prospects for Measuring Black Hole Masses using TDEs with the Vera C. Rubin Observatory

TL;DR

This paper assesses how well the Vera C. Rubin Observatory can measure black hole masses using TDE light curves, highlighting the potential and limitations of this method for understanding black hole populations.

Contribution

It models the impact of Rubin survey strategies on TDE light curve analysis to quantify errors in black hole and stellar mass recovery.

Findings

Black hole masses can be recovered with 0.26 dex error.

Early coverage reduces large outliers in mass estimates.

Only 57% accuracy in determining full or partial disruption.

Abstract

Tidal Disruption Events (TDEs) provide an opportunity to study supermassive black holes that are otherwise quiescent. The Vera C. Rubin Legacy Survey of Space and Time will be capable of discovering thousands of TDEs each year, allowing for a dramatic increase in the number of discovered TDEs. The optical light curves from TDEs can be used to model the physical parameters of the black hole and disrupted star, but the sampling and photometric uncertainty of the real data will couple with model degeneracies to limit our ability to recover these parameters. In this work, we aim to model the impact of the Rubin survey strategy on simulated TDE light curves to quantify the typical errors in the recovered parameters. Black hole masses $5.5< \log M_{\rm BH}/M_\odot < 8.2$ can be recovered with typical errors of 0.26 dex, with early coverage removing large outliers. Recovery of the mass of the disrupted star is difficult, limited by the degeneracy with the accretion efficiency. Only 57\% of the cases have accurate recovery of whether the events are full or partial, so we caution the use this method to assess whether TDEs are partially or fully disrupted systems. Black hole mass measurements obtained from Rubin observations of TDEs will provide powerful constraints on the black hole mass function, black hole -- galaxy co-evolution, and the population of black hole spins, though continued work to understand the origin of TDE observables and how the TDE rate varies among galaxies will be necessarily to fully utilize the upcoming rich data set from Rubin.