A very luminous jet from the disruption of a star by a massive black hole

TL;DR

This paper reports the discovery and analysis of AT2022cmc, a luminous, rapidly fading jetted tidal disruption event at redshift 1.19325, providing insights into the rate and properties of relativistic jets from supermassive black holes.

Contribution

It presents the first optical detection of a jetted TDE at cosmological distance and estimates the on-axis jetted TDE rate using optical survey data.

Findings

AT2022cmc is a luminous, rapidly fading optical transient at z=1.19325.

The estimated rate of on-axis jetted TDEs is 0.02 Gpc$^{-3}$ yr$^{-1}$.

About 1% of TDEs produce relativistic jets, as inferred from the rate analysis.

Abstract

Tidal disruption events (TDEs) are bursts of electromagnetic energy released when supermassive black holes (SMBHs) at the centers of galaxies violently disrupt a star that passes too close. TDEs provide a new window to study accretion onto SMBHs; in some rare cases, this accretion leads to launching of a relativistic jet, but the necessary conditions are not fully understood. The best studied jetted TDE to date is Swift J1644+57, which was discovered in gamma-rays, but was too obscured by dust to be seen at optical wavelengths. Here we report the optical discovery of AT2022cmc, a rapidly fading source at cosmological distance (redshift z=1.19325) whose unique lightcurve transitioned into a luminous plateau within days. Observations of a bright counterpart at other wavelengths, including X-rays, sub-millimeter, and radio, supports the interpretation of AT2022cmc as a jetted TDE containing a synchrotron "afterglow", likely launched by a SMBH with spin $a \gtrsim 0.3$. Using 4 years of Zwicky Transient Facility (ZTF) survey data, we calculate a rate of $0.02 ^{+ 0.04 }_{- 0.01 }$ Gpc$^{-3}$ yr$^{-1}$ for on-axis jetted TDEs based on the luminous, fast-fading red component, thus providing a measurement complementary to the rates derived from X-ray and radio observations. Correcting for the beaming angle effects, this rate confirms that about 1% of TDEs have relativistic jets. Optical surveys can use AT2022cmc as a prototype to unveil a population of jetted TDEs.