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Graham MJ, Ford KES, McKernan B, Ross NP, Stern D, Burdge K, Coughlin M, Djorgovski SG, Drake AJ, Duev D, Kasliwal M, Mahabal AA, van Velzen S, Belecki J, Bellm EC, Burruss R, Cenko SB, Cunningham V, Helou G, Kulkarni SR, Masci FJ, Prince T, Reiley D, Rodriguez H, Rusholme B, Smith RM, Soumagnac MT. Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g. Phys Rev Lett 2020; 124:251102. [PMID: 32639755 DOI: 10.1103/physrevlett.124.251102] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [<O(0.01%))] due to intrinsic variability of this source. The lack of color evolution implies that it is not a supernova and instead is strongly suggestive of a constant temperature shock. Other false-positive events, such as microlensing or a tidal disruption event, are ruled out or constrained to be <O(0.1%). If the flare is associated with S190521g, we find plausible values of total mass M_{BBH}∼100 M_{⊙}, kick velocity v_{k}∼200 km s^{-1} at θ∼60° in a disk with aspect ratio H/a∼0.01 (i.e., disk height H at radius a) and gas density ρ∼10^{-10} g cm^{-3}. The merger could have occurred at a disk migration trap (a∼700r_{g}; r_{g}≡GM_{SMBH}/c^{2}, where M_{SMBH} is the mass of the active galactic nucleus supermassive black hole). The combination of parameters implies a significant spin for at least one of the black holes in S190521g. The timing of our spectroscopy prevents useful constraints on broad-line asymmetry due to an off-center flare. We predict a repeat flare in this source due to a reencountering with the disk in ∼1.6 yr(M_{SMBH}/10^{8} M_{⊙})(a/10^{3}r_{g})^{3/2}.
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Affiliation(s)
- M J Graham
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - K E S Ford
- Department of Science, CUNY-BMCC, 199 Chambers Street, New York, New York 10007, USA
- Department of Astrophysics, American Museum of Natural History, Central Park West, New York, New York 10028, USA
- Physics Program, The Graduate Center, CUNY, New York, New York 10016, USA
| | - B McKernan
- Department of Science, CUNY-BMCC, 199 Chambers Street, New York, New York 10007, USA
- Department of Astrophysics, American Museum of Natural History, Central Park West, New York, New York 10028, USA
- Physics Program, The Graduate Center, CUNY, New York, New York 10016, USA
| | - N P Ross
- Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3 HJ, United Kingdom
| | - D Stern
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - K Burdge
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - M Coughlin
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - S G Djorgovski
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - A J Drake
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - D Duev
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - M Kasliwal
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - A A Mahabal
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - S van Velzen
- Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
- Center for Cosmology and Particle Physics, New York University, New York, New York 10003, USA
| | - J Belecki
- Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA
| | - E C Bellm
- DIRAC Institute, Department of Astronomy, University of Washington, 3910 15th Avenue NE, Seattle, Washington 98195, USA
| | - R Burruss
- Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA
| | - S B Cenko
- Astrophysics Science Division, NASA Goddard Space Flight Center, MC 661, Greenbelt, Maryland 20771, USA
- Joint Space-Science Institute, University of Maryland, College Park, Maryland 20742, USA
| | - V Cunningham
- Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
| | - G Helou
- IPAC, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - S R Kulkarni
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - F J Masci
- IPAC, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - T Prince
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - D Reiley
- Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA
| | - H Rodriguez
- Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA
| | - B Rusholme
- IPAC, California Institute of Technology, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - R M Smith
- Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA
| | - M T Soumagnac
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
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Hung T, Gezari S, Cenko SB, van Velzen S, Blagorodnova N, Yan L, Kulkarni SR, Lunnan R, Kupfer T, Leloudas G, Kong AKH, Nugent PE, Fremling C, Laher RR, Masci FJ, Cao Y, Roy R, Petrushevska T. SIFTING FOR SAPPHIRES: SYSTEMATIC SELECTION OF TIDAL DISRUPTION EVENTS IN iPTF. Astrophys J Suppl Ser 2018; 238:15. [PMID: 31160831 PMCID: PMC6544052 DOI: 10.3847/1538-4365/aad8b1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present results from a systematic selection of tidal disruption events (TDEs) in a wide-area (4800 deg2), g + R band, Intermediate Palomar Transient Factory (iPTF) experiment. Our selection targets typical optically-selected TDEs: bright (>60% flux increase) and blue transients residing in the center of red galaxies. Using photometric selection criteria to down-select from a total of 493 nuclear transients to a sample of 26 sources, we then use follow-up UV imaging with the Neil Gehrels Swift Telescope, ground-based optical spectroscopy, and light curve fitting to classify them as 14 Type Ia supernovae (SNe Ia), 9 highly variable active galactic nuclei (AGNs), 2 confirmed TDEs, and 1 potential core-collapse supernova. We find it possible to filter AGNs by employing a more stringent transient color cut (g - r < -0.2 mag); further, UV imaging is the best discriminator for filtering SNe, since SNe Ia can appear as blue, optically, as TDEs in their early phases. However, when UV-optical color is unavailable, higher precision astrometry can also effectively reduce SNe contamination in the optical. Our most stringent optical photometric selection criteria yields a 4.5:1 contamination rate, allowing for a manageable number of TDE candidates for complete spectroscopic follow-up and real-time classification in the ZTF era. We measure a TDE per galaxy rate of 1.7 - 1.3 + 2.9 × 10 - 4 gal - 1 yr - 1 (90% CL in Poisson statistics). This does not account for TDEs outside our selection criteria, thus may not reflect the total TDE population, which is yet to be fully mapped.
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Affiliation(s)
- T Hung
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
| | - S Gezari
- Department of Astronomy, University of Maryland, College Park, MD 20742, USA
- Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
| | - S B Cenko
- Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
- NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771, USA
| | - S van Velzen
- Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
- Department of Physics, New York University, NY 10003, USA
| | - N Blagorodnova
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lin Yan
- Caltech Optical Observatories, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - S R Kulkarni
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - R Lunnan
- The Oskar Klein Centre & Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - T Kupfer
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - G Leloudas
- Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, 2100 Copenhagen, Denmark
| | - A K H Kong
- Institute of Astronomy, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan
| | - P E Nugent
- Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50B-4206, Berkeley, CA 94720, USA
| | - C Fremling
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - Russ R Laher
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - F J Masci
- Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - Y Cao
- Department of Astronomy, University of Washington, Box 351580, U.W., Seattle, WA 98195-1580, USA
- eScience Institute, University of Washington, Box 351570, U.W., Seattle, WA 98195-1580, USA
| | - R Roy
- The Oskar Klein Centre & Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
| | - T Petrushevska
- Oskar Klein Centre, Department of Physics, Stockholm University, SE 106 91 Stockholm, Sweden
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