Tidal Disruption Flares of Stars From Moderately Recoiled Black Holes

TL;DR

This paper investigates how stellar tidal disruption events caused by recoiled supermassive black holes could serve as observable signatures, with potential detection rates of up to 10 events per year by upcoming surveys like LSST.

Contribution

It provides a quantitative analysis of tidal disruption event rates caused by recoiled black holes across various galaxy and black hole parameters, highlighting their observability.

Findings

Approximately 1 transient accretion disk event per year detectable by LSST.

Super-Eddington tidal flares could produce about 10 observable offset events annually.

Most tidal disruption flares from recoiled black holes are due to bound stars.

Abstract

We analyze stellar tidal disruption events as a possible observational signature of gravitational wave induced recoil of supermassive black holes. As a black hole wanders through its galaxy, it will tidally disrupt bound and unbound stars at rates potentially observable by upcoming optical transient surveys. To quantify these rates, we explore a broad range of host galaxy and black hole kick parameters. We find that emission from a transient accretion disk can produce ~1 event per year which LSST would identify as spatially offset, while super-Eddington tidal flares, if they exist, are likely to produce ~10 spatially offset events per year. A majority of tidal disruption flares, and a large majority of flares with an observable spatial offset, are due to bound rather than unbound stars. The total number of disruption events due to recoiled black holes could be almost 1% of the total stellar tidal disruption rate.