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The electromagnetic counterpart of the binary neutron star merger LIGO/VIRGO GW170817. II. UV, optical, and near-IR light curves and comparison to kilonova models

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  • P. S. Cowperthwaite
  • E. Berger
  • V. A. Villar
  • B. D. Metzger
  • M. Nicholl
  • R. Chornock
  • P. K. Blanchard
  • W. Fong
  • R. Margutti
  • M. Soares-Santos
  • K. D. Alexander
  • S. Allam
  • J. Annis
  • D. Brout
  • D. A. Brown
  • R. E. Butler
  • H. -Y. Chen
  • H. T. Diehl
  • Z. Doctor
  • M. R. Drout
  • T. Eftekhari
  • B. Farr
  • D. A. Finley
  • R. J. Foley
  • J. A. Frieman
  • C. L. Fryer
  • J. García-Bellido
  • M. S. S. Gill
  • J. Guillochon
  • K. Herner
  • D. E. Holz
  • D. Kasen
  • R. Kessler
  • J. Marriner
  • T. Matheson
  • Jr E. H. Neilsen
  • E. Quataert
  • A. Palmese
  • A. Rest
  • M. Sako
  • D. M. Scolnic
  • N. Smith
  • D. L. Tucker
  • P. K. G. Williams
  • E. Balbinot
  • J. L. Carlin
  • E. R. Cook
  • F. Durret
  • T. S. Li
  • P. A. A. Lopes
  • A. C. C. Lourenço
  • J. L. Marshall
  • G. E. Medina
  • J. Muir
  • R. R. Muñoz
  • M. Sauseda
  • D. J. Schlegel
  • L. F. Secco
  • A. K. Vivas
  • W. Wester
  • A. Zenteno
  • Y. Zhang
  • T. M. C. Abbott
  • M. Banerji
  • K. Bechtol
  • A. Benoit-Lévy
  • E. Bertin
  • E. Buckley-Geer
  • D. L. Burke
  • D. Capozzi
  • A. Carnero Rosell
  • M. Carrasco Kind
  • F. J. Castander
  • M. Crocce
  • C. E. Cunha
  • C. B. D'Andrea
  • L. N. da Costa
  • C. Davis
  • D. L. DePoy
  • S. Desai
  • J. P. Dietrich
  • A. Drlica-Wagner
  • T. F. Eifler
  • A. E. Evrard
  • E. Fernandez
  • B. Flaugher
  • P. Fosalba
  • E. Gaztanaga
  • D. W. Gerdes
  • T. Giannantonio
  • D. A. Goldstein
  • D. Gruen
  • R. A. Gruendl
  • G. Gutierrez
  • K. Honscheid
  • B. Jain
  • D. J. James
  • T. Jeltema
  • M. W. G. Johnson
  • M. D. Johnson
  • S. Kent
  • E. Krause
  • R. Kron
  • K. Kuehn
  • N. Kuropatkin
  • O. Lahav
  • M. Lima
  • H. Lin
  • M. A. G. Maia
  • M. March
  • P. Martini
  • R. G. McMahon
  • F. Menanteau
  • C. J. Miller
  • R. Miquel
  • J. J. Mohr
  • E. Neilsen
  • R. L. C. Ogando
  • A. A. Plazas
  • N. Roe
  • A. K. Romer
  • A. Roodman
  • E. S. Rykoff
  • E. Sanchez
  • V. Scarpine
  • R. Schindler
  • M. Schubnell
  • I. Sevilla-Noarbe
  • M. Smith
  • R. C. Smith
  • F. Sobreira
  • E. Suchyta
  • M. E. C. Swanson
  • G. Tarle
  • R. C. Thomas
  • M. A. Troxel
  • V. Vikram
  • A. R. Walker
  • R. H. Wechsler
  • J. Weller
  • B. Yanny
  • J. Zuntz
We present UV, optical, and near-infrared (NIR) photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at 0.47–18.5 days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), and the Hubble Space Telescope (HST). The spectral energy distribution (SED) inferred from this photometry at 0.6 days is well described by a blackbody model with T ≈ 8300 K, a radius of R ≈ 4.5 x 1014 cm (corresponding to an expansion velocity of v ≈ 0.3c), and a bolometric luminosity of Lbol ≈ 5 x 1041 erg s−1. At 1.5 days we find a multi-component SED across the optical and NIR, and subsequently we observe rapid fading in the UV and blue optical bands and significant reddening of the optical/NIR colors. Modeling the entire data set, we find that models with heating from radioactive decay of 56Ni, or those with only a single component of opacity from r-process elements, fail to capture the rapid optical decline and red optical/NIR colors. Instead, models with two components consistent with lanthanide-poor and lanthanide-rich ejecta provide a good fit to the data; the resulting "blue" component has M ej blue ≈ 0.01M⊙  and v ej blue ≈ 0.3 c, and the "red" component has M ej red ≈ 0.04 M⊙ and v ej red ≈ 0.1 c. These ejecta masses are broadly consistent with the estimated r-process production rate required to explain the Milky Way r-process abundances, providing the first evidence that binary neutron star (BNS) mergers can be a dominant site of r-process enrichment.
Original languageEnglish
JournalAstrophysical Journal Letters
Issue number2
Publication statusPublished - 16 Oct 2017


  • 1710.05840v1

    Rights statement: The final published version of this article by P. S. Cowperthwaite et al 2017 ApJL 848 L17 is available online at © 2017. The American Astronomical Society. All rights reserved.

    Accepted author manuscript (Post-print), 454 KB, PDF document

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