eROSITA Detection Rates for Tidal Disruptions of White Dwarfs by Intermediate Mass Black Holes

TL;DR

This study assesses eROSITA's ability to detect white dwarf tidal disruption events caused by intermediate mass black holes, estimating detection rates and sensitivities through simulations and rate density calculations.

Contribution

It introduces a comprehensive simulation framework and new rate density estimates for WTDEs, enhancing understanding of eROSITA's detection potential.

Findings

eROSITA may detect about 3 WTDEs during its 4-year survey.

Sensitivity is highest for black holes above 10^4 solar masses.

Most WTDEs are detectable within 5 days of the flare.

Abstract

White dwarf-black hole tidal disruption events (herein WTDEs) present an opportunity to probe the quiescent intermediate mass black hole population in the universe. We run an extensive set of Monte-Carlo based simulations to explore SRG/eROSITA's detection sensitivity to WTDEs as a function of black hole mass, redshift and time offset between event flaring and it first being observed. A novel estimate of WTDE rate densities from globular clusters and dwarf galaxies is also presented. We combine this with estimated detection sensitivities to infer the rate of eROSITA detecting these events. Depending on the estimate of the intrinsic rate of WTDEs, we anticipate that eROSITA may detect $\sim 3$ events over its 4 year all-sky survey. eROSITA will be most sensitive to systems with black hole masses above $10^4M_{\odot}$, and is most likely to catch these within 5 days of flaring.