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 have the potential to unveil cosmological (redshift z > 1) quiescent black holes and are ideal test beds for understanding the radiative mechanisms operating in super-Eddington jets. Here we present multiwavelength (X-ray, UV, optical and radio) observations of the optically discovered transient AT 2022cmc at z = 1.193. Its unusual X-ray properties, including a peak observed luminosity of ≳1048 erg s−1, systematic variability on timescales as short as 1,000 s and overall duration lasting more than 30 days in the rest frame, are traits associated with relativistic tidal disruption events. 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 tidal disruption events (UV/optical). Our modelling implies a beamed, highly relativistic jet akin to blazars but requires extreme matter domination (that is, a high ratio of electron-to-magnetic-field energy densities in the jet) and challenges our theoretical understanding of jets.
Bibliographical noteFunding Information:
D.R.P. would like to thank S. Dicker for sharing details of the GBT observations. D.R.P. was supported by NASA grant number 80NSSC22K0961 for this work. S.J.B. would like to thank Science Foundation Ireland and the Royal Society (grant number RS-EA/3471) for their support. S. Schulze acknowledges support from the G.R.E.A.T. research environment, funded by Vetenskapsrådet, the Swedish Research Council, under project number 2016-06012. F.O. acknowledges support from MIUR, PRIN 2017 (grant number 20179ZF5KS) “The new frontier of the Multi-Messenger Astrophysics: follow-up of electromagnetic transient counterparts of gravitational wave sources” and the support of HORIZON2020: AHEAD2020 grant agreement number 871158. G.L. and P.C. were supported by a research grant (number 19054) from VILLUM FONDEN. N.C.S. acknowledges support from the Science and Technology Facilities Council (STFC), and from STFC grant number ST/M001326/. M.N., B.P.G., A.A., E.J.R. and X.S. are supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement number 948381). L.R. acknowledges the support given by the Science and Technology Facilities Council through an STFC studentship. T.L. acknowledges support from the Radboud Excellence Initiative. T.M.B. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN), the Agencia Estatal de Investigación (AEI) 10.13039501100011033 under the PID2020-115253GA-I00 HOSTFLOWS project, from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016 and the I-LINK 2021 LINKA20409 and the programme Unidad de Excelencia María de Maeztu CEX2020-001058-M. C.-C.N. thanks the Ministry of Science and Technology (Taiwan) for funding under the contract 109-2112-M-008-014-MY3. M.P.T. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and through the grant PID2020-117404GB-C21 (MCI/AEI/FEDER, UE). Support for A.C. was provided by ANID through grant number ICN12_12009 awarded to the Millennium Institute of Astrophysics (MAS) and by ANID’s Basal projects AFB-170002 and FB210003. E.R.C. acknowledges support from the National Science Foundation through grant number AST-2006684, and a Ralph E. Powe Junior Faculty Enhancement Award through the Oakridge Associated Universities. Pan-STARRS is a project of the Institute for Astronomy of the University of Hawaii, and is supported by the NASA SSO Near Earth Observation Program under grant numbers 80NSSC18K0971, NNX14AM74G, NNX12AR65G, NNX13AQ47G, NNX08AR22G and 80NSSC21K1572 and by the State of Hawaii. This publication has made use of data collected at Lulin Observatory, partly supported by MoST grant number 108-2112-M-008-001. We thank Lulin staff H.-Y. Hsiao, C.-S. Lin, W.-J. Hou and J.-K. Guo for observations and data management. This work was supported by the Australian government through the Australian Research Council’s Discovery Projects funding scheme (DP200102471). The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg, and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under grant number NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation grant number AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory and the Gordon and Betty Moore Foundation. R.R. and D.R.P. acknowledge partial support from the NASA grant number 80NSSC19K1287, for contributions to NICER. The European VLBI Network is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from EVN project code RM017A. e-VLBI research infrastructure in Europe is supported by the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number RI-261525 NEXPReS. A.H. is grateful for support by the I-Core Program of the Planning and Budgeting Committee and the Israel Science Foundation, and support under ISF grant number 647/18. This research was supported by grant number 2018154 from the United States-Israel Binational Science Foundation (BSF). We acknowledge the staff who operate and run the AMI-LA telescope at Lord’s Bridge, Cambridge, for the AMI-LA radio data. AMI is supported by the Universities of Cambridge and Oxford, and by the European Research Council under grant number ERC-2012-StG-307215 LODESTONE. NICER is a 0.2–12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA. The AstroSat mission is operated by the Indian Space Research Organisation (ISRO), the data are archived at the Indian Space Science Data Centre (ISSDC). The SXT data-processing software is provided by the Tata Institute of Fundamental Research (TIFR), Mumbai, India. The UVIT data were checked and verified by the UVIT POC at IIA, Bangalore, India. M.G. is supported by the EU Horizon 2020 research and innovation programme under grant agreement number 101004719. L.S. acknowledges support by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Advanced Grant KILONOVA number 885281). M.P.T. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (grant number SEV-2017-0709) and through grant number PID2020-117404GB-C21 (MCI/AEI/FEDER, UE). Support for this work was provided by NASA through the Smithsonian Astrophysical Observatory (SAO) contract number SV3-73016 to MIT for Support of the Chandra X-Ray Center (CXC) and Science Instruments. S.Y. has been supported by the research project grant “Understanding the Dynamic Universe” funded by the Knut and Alice Wallenberg Foundation under Dnr KAW 2018.0067, and the G.R.E.A.T research environment, funded by Vetenskapsrådet, the Swedish Research Council, project number 2016-06012. S.J.S., SS and K.W.S. acknowledge funding from STFC grant numbers ST/T000198/1 and ST/S006109/1. I.A. is a CIFAR Azrieli Global Scholar in the Gravity and the Extreme Universe Program and acknowledges support from that programme, from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement number 852097), from the Israel Science Foundation (grant number 2752/19), from the United States–Israel Binational Science Foundation (BSF), and from the Israeli Council for Higher Education Alon Fellowship. E.F. is supported by NASA under award number 80GSFC21M0002. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. G.P.S. acknowledges support from The Royal Society, the Leverhulme Trust and the Science and Technology Facilities Council (grant numbers ST/N021702/1 and ST/S006141/1). L.G. acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN), the Agencia Estatal de Investigación (AEI) 10.13039/501100011033, and the European Social Fund (ESF) “Investing in your future” under the 2019 Ramón y Cajal programme RYC2019-027683-I and the PID2020-115253GA-I00 HOSTFLOWS project, from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016 and the programme Unidad de Excelencia María de Maeztu CEX2020-001058-M. ECF is supported by NASA under award number 80GSFC21M0002. This work was completed in part using the Discovery cluster, supported by Northeastern University’s Research Computing team.
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