Title: The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole?

Abstract

Wide-field optical surveys have begun to uncover large samples of fast (^trise ≲ 5 d), luminous (^Mpeak < -18), blue transients. While commonly attributed to the breakout of a supernova shock into a dense wind, the great distances to the transients of this class found so far have hampered detailed investigation of their properties. We present photometry and spectroscopy from a comprehensive worldwide campaign to observe AT 2018cow (ATLAS 18qqn), the first fast-luminous optical transient to be found in real time at low redshift. Our first spectra (<2 days after discovery) are entirely featureless. A very broad absorption feature suggestive of near-relativistic velocities develops between 3 and 8 days, then disappears. Broad emission features of H and He develop after >10 days. The spectrum remains extremely hot throughout its evolution, and the photospheric radius contracts with time (receding below R < 10¹⁴ cm after 1 month). Furthermore, this behavior does not match that of any known supernova, although a relativistic jet within a fallback supernova could explain some of the observed features. Alternatively, the transient could originate from the disruption of a star by an intermediate-mass black hole, although this would require long-lasting emission of highly super-Eddington thermal radiation. Inmore » either case, AT 2018cow suggests that the population of fast luminous transients represents a new class of astrophysical event. Intensive follow-up of this event in its late phases, and of any future events found at comparable distance, will be essential to better constrain their origins.« less

Authors:

Perley, Daniel A.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8472-1996"

Mazzali, Paolo A. ^[2]; Yan, Lin ^[3]; Cenko, S. Bradley ^[4]; Gezari, Suvi ^[5]; Taggart, Kirsty ^[1]; Blagorodnova, Nadia ^[3]; Fremling, Christoffer ^[3]; Mockler, Brenna ^[6]; Singh, Avinash  ^[7];

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Tominaga, Nozomu ^[8]; Tanaka, Masaomi ^[9]; Watson, Alan M. ^[10]; Ahumada, Tomás ^[5]; Anupama, G. C. ^[11]; Ashall, Chris ^[12]; Becerra, Rosa L. ^[10]; Bersier, David ^[1]; Bhalerao, Varun ^[13]; Bloom, Joshua S. ^[14] more »; Butler, Nathaniel R. ^[15]; Copperwheat, Chris ^[1]; Coughlin, Michael W.  ^[3];

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De, Kishalay ^[3]; Drake, Andrew J. ^[3]; Duev, Dmitry A. ^[3]; Frederick, Sara ^[5]; González, J. Jesús ^[10]; Goobar, Ariel  ^[16];

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Heida, Marianne  ^[3];

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Ho, Anna Y. Q. ^[3]; Horst, John ^[17]; Hung, Tiara ^[5]; Itoh, Ryosuke ^[18]; Jencson, Jacob E. ^[3]; Kasliwal, Mansi M.  ^[3];

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Kawai, Nobuyuki ^[18]; Khanam, Tanazza ^[13]; Kulkarni, Shrinivas R. ^[19]; Kumar, Brajesh  ^[11];

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Kumar, Harsh ^[13]; Kutyrev, Alexander S. ^[4]; Lee, William H. ^[10]; Maeda, Keiichi ^[20]; Mahabal, Ashish ^[21]; Murata, Katsuhiro L. ^[18]; Neill, James D. ^[3]; Ngeow, Chow-Choong ^[22]; Penprase, Bryan ^[23]; Pian, Elena ^[24]; Quimby, Robert ^[25]; Ramirez-Ruiz, Enrico ^[26]; Richer, Michael G. ^[10]; Román-Zúñiga, Carlos G.  ^[27];

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Sahu, D. K. ^[11]; Srivastav, Shubham ^[13]; Socia, Quentin ^[17]; Sollerman, Jesper ^[28]; Tachibana, Yutaro  ^[18];

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Taddia, Francesco ^[28]; Tinyanont, Samaporn ^[3]; Troja, Eleonora ^[4]; Ward, Charlotte ^[5]; Wee, Jerrick ^[29]; Yu, Po-Chieh ^[22] « less

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+ Show Author Affiliations

1. Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
2. Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK, Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str 1, D-84741 Garching, Germany
3. Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
4. Astrophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, USA, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
5. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
6. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark, Department of Astronomy, University of Maryland, College Park, MD 20742, USA
7. Indian Institute of Astrophysics, II Block Koramangala, Bengaluru 560034, India, Joint Astronomy Programme, Department of Physics, Indian Institute of Science, Bengaluru 560012, India
8. Kavli IPMU (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan, Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501, Japan
9. Astronomical Institute, Tohoku University, Aoba, Sendai 980-8578, Japan
10. Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70-264, 04510 México, CDMX, México
11. Indian Institute of Astrophysics, II Block Koramangala, Bengaluru 560034, India
12. Department of Physics, Florida State Universiy, Tallahassee, FL 32306, USA
13. Physics Department, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
14. Department of Astronomy, University of California, Berkeley, CA 94720, USA
15. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
16. The Oskar Klein Centre, Department of Physics, AlbaNova, Stockholm University, SE-106 91 Stockholm, Sweden
17. Department of Astronomy/Mount Laguna Observatory, San Diego State University, 5500 Campanile Drive, San Diego, CA 92812-1221, USA
18. Department of Physics, School of Science, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro, Tokyo 152-8551, Japan
19. Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA, Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125, USA
20. Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
21. Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA, Center for Data Driven Discovery, California Institute of Technology, Pasadena, CA 91125, USA
22. Graduate Institute of Astronomy, National Central University, 32001 Taipei , Taiwan
23. Soka University of America, 1 University Drive, Aliso Viejo, CA 92656, USA
24. INAF OAS, Via Piero Gobetti, 101, I-40129 Bologna, Italy
25. Kavli IPMU (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan, Department of Astronomy/Mount Laguna Observatory, San Diego State University, 5500 Campanile Drive, San Diego, CA 92812-1221, USA
26. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
27. Instituto de Astronomía UNAM, Unidad Académica en Ensenada, 22860 Ensenada BC, México
28. The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-106 91 Stockholm, Sweden
29. Yale-NUS College, 16 College Avenue West, Singapore 138527, Singapore

Publication Date:

Sat Dec 22 00:00:00 EST 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1491926

Alternate Identifier(s):

OSTI ID: 1571983

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 484 Journal Issue: 1; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; Black hole; stars; supernovae: general; supernova: individual: AT2018cow