Fallback Rates from Partial Tidal Disruption Events

Abstract

A tidal disruption event (TDE) occurs when a star plunges through a supermassive black hole's tidal radius, at which point the star's self-gravity is overwhelmed by the tidal gravity of the black hole. In a partial TDE, where the star does not reach the full disruption radius, only a fraction of the star's mass is tidally stripped while the rest remains intact in the form of a surviving core. Analytical arguments have recently suggested that the temporal scaling of the fallback rate of debris to the black hole asymptotes to $t^{-9/4}$ for partial disruptions, effectively independently of the mass of the intact core. We present hydrodynamical simulations that verify the existence of this predicted, $t^{-9/4}$ scaling. We also define a break timescale -- the time at which the fallback rate transitions from a $t^{-5/3}$ scaling to the characteristic $t^{-9/4}$ scaling -- and measure this break timescale as a function of the impact parameter and the surviving core mass. These results deepen our understanding of the properties and breadth of possible fallback curves expected from TDEs and will therefore facilitate more accurate interpretation of data from wide-field surveys.

Accepted for publication in The Astrophysical Journal, 13th June 2020. 11 pages, 8 figures

References in corpus (8)

• Stellar disruption by a supermassive black hole: is the light curve really proportional to $t^{-5/3}$?
• General Relativistic Hydrodynamic Simulation of Accretion Flow from a Stellar Tidal Disruption
• Long-term stream evolution in tidal disruption events
• Tidal disruptions by rotating black holes: effects of spin and impact parameter
• Tidal disruption events from supermassive black hole binaries
• Radio observations of the tidal disruption event XMMSL1 J0740$-$85
• Tidal disruption events: the role of stellar spin
• Relativistic effects on tidal disruption kicks of solitary stars

Cited by in corpus (2)

• Partial tidal disruption events by stellar mass black holes: gravitational instability of stream and impact from remnant core
• Structured, relativistic jets driven by radiation