Constraining the Rate of Relativistic Jets from Tidal Disruptions Using Radio Surveys

Abstract

Tidal disruption of stars by massive black holes produce transient accretion flows that flare at optical, UV, and X-ray wavelengths. At late times, these accretion flows may launch relativistic jets that can be detected through the interaction of the jet with the dense interstellar medium of the galaxy. We present an upper limit for the flux density of a radio counterpart to a tidal disruption event detected by GALEX that is a factor of 6 below theoretical predictions. We also examine existing radio surveys for transients with a time scale of 1 year and use these to set a $2 \sigma$ upper limit on the rate of tidal disruption events producing relativistic jets of ~14 x 10^-7 Mpc^-3 y^-1. This rate is an order of magnitude lower than the highest values from theoretical models and is consistent with detection rates from optical and X-ray surveys.Comment: Accepted for publication in ApJ