Measuring stellar and black hole masses of tidal disruption events

TL;DR

This paper introduces a new physical model and a computational tool, TDEmass, to accurately estimate black hole and star masses from tidal disruption event light curves, based on optical/UV observations.

Contribution

The paper presents a novel method and open-source tool for inferring black hole and star masses from TDE optical/UV data, improving mass measurement accuracy.

Findings

Black hole masses range from 5×10^5 to 10^7 solar masses.

Disrupted star masses range from 0.6 to 13 solar masses.

The method successfully applied to 21 well-measured TDEs.

Abstract

The flare produced when a star is tidally disrupted by a supermassive black hole holds potential as a diagnostic of both the black hole mass and the star mass. We propose a new method to realize this potential based upon a physical model of optical/UV light production in which shocks near the apocenters of debris orbits dissipate orbital energy, which is then radiated from that region. Measurement of the optical/UV luminosity and color temperature at the peak of the flare leads directly to the two masses. The black hole mass depends mostly on the temperature observed at peak luminosity, while the mass of the disrupted star depends mostly on the peak luminosity. We introduce {\sc TDEmass}, a method to infer the black hole and stellar masses given these two input quantities. Using {\sc TDEmass}, we find, for 21 well-measured events, black hole masses between $5\times 10^5$ and $10^7 M_\odot$ and disrupted stars with initial masses between 0.6 and $13M_\odot$. An open-source {\sc python}-based tool for {\sc TDEmass} is available at https://github.com/taehoryu/TDEmass.git.