Multiple Tidal Disruptions as an Indicator of Binary Super-Massive Black Hole Systems

TL;DR

Multiple tidal disruption events can serve as indicators of binary super-massive black hole systems, with detectable rates by LSST, offering a new method to identify such binaries at parsec to sub-parsec scales.

Contribution

This study introduces a novel approach to identify binary SMBH systems through the detection of multiple tidal disruptions, supported by simulations of stellar dynamics around SMBHs.

Findings

LSST can detect multiple tidal disruptions in about 3 galaxies over 5 years.

The rate of detectable events could increase by an order of magnitude with less conservative estimates.

Binary SMBH systems are likely to produce observable multiple tidal disruption events.

Abstract

We find that the majority of systems hosting multiple tidal disruptions are likely to contain hard binary SMBH systems, and also show that the rates of these repeated events are high enough to be detected by LSST over its lifetime. Therefore, these multiple tidal disruption events provide a novel method to identify super-massive black hole (SMBH) binary systems with parsec to sub-parsec separations. The rates of tidal disruptions are investigated using simulations of non-interacting stars initially orbiting a primary SMBH and the potential of the model stellar cusp. The stars are then evolved forward in time and perturbed by a secondary SMBH inspiraling from the edge of the cusp to its stalling radius. We find with conservative magnitude estimates that the next generation transient survey LSST should detect multiple tidal disruptions in approximately 3 galaxies over 5 years of observation, though less conservative estimates could increase this rate by an order of magnitude.