The rate of stellar tidal disruption flares from SDSS data

TL;DR

This paper estimates the rate of stellar tidal disruption flares using SDSS archival data, identifying two strong candidates and calculating a rate of approximately 3x10^-5 per galaxy per year, with an upper limit of 3x10^-4.

Contribution

It provides the first observational estimate of TDF rates from SDSS data, employing a novel pipeline to distinguish nuclear flares and simulate detection efficiency.

Findings

Detected 186 nuclear flares, including 2 TDF candidates.

Estimated TDF rate: 3x10^-5 per galaxy per year.

Upper limit on TDF rate: <3x10^-4 per galaxy per year.

Abstract

We report an observational estimate of the rate of stellar tidal disruption flares (TDFs), based on our (successful) search for these events in archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data. Our pipeline took advantage of the excellent astrometry of SDSS to separate nuclear flares from supernovae. The 10 year baseline and the high cadence of the observations facilitate a clear-cut identification of variable active galactic nuclei. We found 186 nuclear flares, of which two are excellent TDF candidates. To compute the rate of (optical) stellar tidal disruption events, we simulate our entire pipeline to obtain the efficiency of detection for a given light curve. Using a simple model to extrapolate the observed light curves forward and backward in time, we find our best-estimate of the TDF rate: 3x10-5 per galaxy per year. In addition, we give a model-independent upper limit to the TDF rate: < 3x10-4 per galaxy per year (90% CL).