The Birth of a Relativistic Jet Following the Disruption of a Star by a Cosmological Black Hole

Dheeraj R. Pasham, Matteo Lucchini, Tanmoy Laskar, Benjamin P. Gompertz, Shubham Srivastav, Matt Nicholl, Stephen J. Smartt, James C. A. Miller-Jones, Kate D. Alexander, Rob Fender, Graham P. Smith, Michael D. Fulton, Gulab Dewangan, Keith Gendreau, Eric R. Coughlin, Lauren Rhodes, Assaf Horesh, Sjoert van Velzen, Itai Sfaradi, Muryel Guolo, N. Castro Segura, Aysha Aamer, Joseph P. Anderson, Iair Arcavi, Sean J. Brennan, Kenneth Chambers, Panos Charalampopoulos, Ting-Wan Chen, A. Clocchiatti, Thomas de Boer, Michel Dennefeld, Elizabeth Ferrara, Lluis Galbany, Hua Gao, James H. Gillanders, Adelle Goodwin, Mariusz Gromadzki, M Huber, Peter G. Jonker, Manasvita Joshi, Erin Kara, Thomas L. Killestein, Peter Kosec, Daniel Kocevski, Giorgos Leloudas, Chien-Cheng Lin, Raffaella Margutti, Seppo Mattila, Thomas Moore, Tomas Muller-Bravo, Chow-Choong Ngeow, Samantha Oates, Francesca Onori, Yen-Chen Pan, Miguel Perez-Torres, Priyanka Rani, Ronald Remillard, Evan J. Ridley, Steve Schulze, Xinyue Sheng, Luke Shingles, Ken W. Smith, James Steiner, Richard Wainscoat, Thomas Wevers, Sheng Yang

Published 2022-11-29Version 1

A black hole can launch a powerful relativistic jet after it tidally disrupts a star. If this jet fortuitously aligns with our line of sight, the overall brightness is Doppler boosted by several orders of magnitude. Consequently, such on-axis relativistic tidal disruption events (TDEs) have the potential to unveil cosmological (redshift $z>$1) quiescent black holes and are ideal test beds to understand the radiative mechanisms operating in super-Eddington jets. Here, we present multi-wavelength (X-ray, UV, optical, and radio) observations of the optically discovered transient \target at $z=1.193$. Its unusual X-ray properties, including a peak observed luminosity of $\gtrsim$10$^{48}$ erg s$^{-1}$, systematic variability on timescales as short as 1000 seconds, and overall duration lasting more than 30 days in the rest-frame are traits associated with relativistic TDEs. The X-ray to radio spectral energy distributions spanning 5-50 days after discovery can be explained as synchrotron emission from a relativistic jet (radio), synchrotron self-Compton (X-rays), and thermal emission similar to that seen in low-redshift TDEs (UV/optical). Our modeling implies a beamed, highly relativistic jet akin to blazars but requires extreme matter-domination, i.e, high ratio of electron-to-magnetic field energy densities in the jet, and challenges our theoretical understanding of jets.