Micro-Tidal Disruption Events at Galactic Centers

Abstract: In this work, we discuss a scenario of a micro-Tidal Disruption Event (TDE) associated with high-speed white dwarfs and stellar-mass black holes. It happens at galactic centers, where a white dwarf orbiting around the massive black hole scatters with a stellar-mass black hole in its early extreme mass-ratio inspiral stage. We estimate the formation rate, perform a series of hydro simulations to investigate the amount of accreted and unbound mass as a function of impact radius and speed, and discuss the main EM signatures: an X-ray flare (micro-TDE) followed by a relatively faint (TDE-type) optical flare. The properties of some of the transient X-ray bursts found by Einstein Probe are consistent with the micro-TDE scenario considered here.