Radio jets from stellar tidal disruptions

TL;DR

This paper models radio emissions from jets formed during stellar tidal disruption events, predicting their detectability and rate, and compares the model to observed data, suggesting future radio surveys can test jet occurrence in such events.

Contribution

It introduces an empirically-based model linking accretion rates to jet luminosity in tidal disruption events, enabling predictions of radio transient rates.

Findings

Model reproduces radio flux of GRB 110328A

Predicts detectable radio transient rates for future surveys

Suggests most tidal disruptions may produce jets

Abstract

A star that passes too close to a massive black hole will be torn apart by tidal forces. The flare of photons emitted during the accretion of the stellar debris is predicted to be observable and candidates of such events have been observed at optical to X-ray frequencies. If a fraction of the accreted material is fed into a jet, tidal flares should be detectable at radio frequencies too, thus comprising a new class of rare radio transients. Using the well-established scaling between accretion power and jet luminosity and basic synchrotron theory, we construct an empirically-rooted model to predict the jet luminosity for a time-dependent accretion rate. We apply this model to stellar tidal disruptions and predict the snapshot rate of these events. For a small angle between the observer and the jet, our model reproduces the observed radio flux of the tidal flare candidate GRB 110328A. We find that future radio surveys will be able to test whether the majority of tidal disruptions are accompanied by a jet.