Changing look quasars from tidal disruption flares

Hamsa Padmanabhan, Abraham Loeb

Published 2020-03-16Version 1

We explore the contributions of Tidal Disruption Events (TDEs) as potential triggers for Active Galactic Nuclei (AGN). Using the latest data available from X-ray and optical observations of high-redshift galaxies, as well as the evolution of their central supermassive black holes, we calculate the extent to which TDEs trigger AGN as a function of their luminosities. We find that at low redshifts ($z < 1$), a few percent of all AGN with bolometric luminosities $L_{\rm Bol} \lesssim 10^{44}$ erg s$^{-1}$ may be attributable to TDE triggers. However, this fraction can significantly increase at earlier cosmic times, reaching several tens of percent at $z > 2$, including about 20-50% of the observed population of Changing Look Quasars (CLQs). TDEs may comprise a significant fraction of the Compton-Thick (CT) AGN population at $z > 2$. The above findings motivate further calibration from upcoming X-ray missions and spectroscopic surveys targeting TDE-AGN.