A nearby long gamma-ray burst from a merger of compact objects

E. Troja, C. L. Fryer, B. O’Connor, G. Ryan, S. Dichiara, A. Kumar, N. Ito, R. Gupta, R. T. Wollaeger, J. P. Norris, N. Kawai, N. R. Butler, A. Aryan, K. Misra, R. Hosokawa, K. L. Murata, M. Niwano, S. B. Pandey, A. Kutyrev, H. J. van EertenE. A. Chase, Y. D. Hu, M. D. Caballero-Garcia, A. J. Castro-Tirado

Research output: Contribution to journalArticlepeer-review

78 Citations (SciVal)


Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4–6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger.

Original languageEnglish
Pages (from-to)228-231
Number of pages4
Issue number7939
Early online date7 Dec 2022
Publication statusPublished - 8 Dec 2022

Bibliographical note

Funding Information:
This work was supported by the European Research Council through the Consolidator grant BHianca (grant agreement ID 101002761) and by the National Science Foundation (under award number 12850). B.O’C. was partially supported by the National Aeronautics and Space Administration (NASA) through grants NNX16AB66G, NNX17AB18G and 80NSSC20K0389. N.K. was financially supported by Grants-in-Aid for Scientific Research 17H06362 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. This work was partially supported by the Optical and Near-Infrared Astronomy Inter-University Cooperation Program of the MEXT of Japan, and the joint research programme of the Institute for Cosmic Ray Research (ICRR), the University of Tokyo. Research at Perimeter Institute is supported in part by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Colleges and Universities. The development of afterglow models used in this work was partially supported by the European Union Horizon 2020 programme under the AHEAD2020 project (grant agreement number 871158). C.L.F., E.A.C. and R.W. are supported by the US Department of Energy through the Los Alamos National Laboratory (LANL), operated by Triad National Security, LLC, for the National Nuclear Security Administration of US Department of Energy (contract no. 89233218CNA000001). This work includes observations obtained at the international Gemini Observatory (principal investigator (PI): B.O’C.; GS-2022A-Q-141), a programme of NSF’s NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the NSF on behalf of the Gemini Observatory partnership: the NSF (USA), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovacíon (Argentina), Ministério da Cieˆncia, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). The HST data (ObsID: 16846; PI: E.T.) used in this work was obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. This research is partially based on observations under our ToO proposal number DOT-2021-C2-P71 (PI: R.G.) and proposal number DOT-2021-C2-P54 (PI: S.B.P.) obtained at the 3.6-m Devasthal Optical Telescope (DOT), which is a National Facility run and managed by Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous Institute under the Department of Science and Technology, Government of India. R.G. and S.B.P. acknowledge all the observing and support staff of the 3.6-m DOT and 1.3-m DFOT for maintaining and running the observational facilities at Devasthal Nainital. R.G. is especially thankful to B. Kumar, A. K. Ror and M. Sarkar for the observations with the 3.6-m DOT and 1.3-m DFOT under the approved observing proposals: DOT-2021-C2-P71 (PI: R.G.), DFOT-2021B-P29 (PI: R.G.), and DOT-2021-C2-P54 (PI: S.B.P.). R.G., A.A., K.M. and S.B.P. acknowledge the BRICS grant (DST/IMRCD/BRICS/PilotCall1/ProFCheap/2017(G)) for financial support. R.G. and S.B.P. also acknowledge the financial support of ISRO under the AstroSat archival data utilization programme (DS_2B-13013(2)/1/2021-Sec.2). A.A. acknowledges funds and assistance provided by the Council of Scientific & Industrial Research (CSIR), India with file no. 09/948(0003)/2020-EMR-I. M.D.C.-G. acknowledges support from the Ramón y Cajal Fellowship RYC2019-026465-I. Y.-D.H. acknowledges support under the additional funding from RYC2019-026465-I. A.J.C.-T. acknowledges support from the Spanish Ministry project PID2020-118491GB-I00, Junta de Andalucia project P20_01068 and the ‘Center of Excellence Severo Ochoa’ award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). Based on observations collected at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (ToO Program 21B-2.2-028: PI: A.J.C.-T.), operated jointly by Junta de Andalucía and Consejo Superior de Investigaciones Científicas (IAA-CSIC). These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy and operates the LDT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University and Yale University. This research used resources provided by the LANL Institutional Computing Program. Figure was created with the help of the NOIRLab/IPAC/ESA/STScI/CfA FITS Liberator. We made use of IRAF, which is distributed by the NSF NOIRLab. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.

Data availability
Data from NASA’s missions are publicly available from the High Energy Astrophysics Science Archive Research Center (HEASARC) at https://heasarc.gsfc.nasa.gov. Swift XRT products are available from the online GRB repository https://www.swift.ac.uk/xrt_products. Other data are available from the corresponding author upon reasonable request. The broad grid of kilonova models is publicly available at https://doi.org/10.5281/zenodo.5745556.

ASJC Scopus subject areas

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