Article open access publication

Electromagnetic evidence that SSS17a is the result of a binary neutron star merger

Science, American Association for the Advancement of Science (AAAS), ISSN 0036-8075

Volume 358, 6370, 2017

DOI:10.1126/science.aaq0073, Dimensions: pub.1092247861, PMID: 29038369,



  1. (1) University of California, Santa Cruz, grid.205975.c
  2. (2) Lawrence Berkeley National Laboratory, grid.184769.5
  3. (3) University of California, Berkeley, grid.47840.3f
  4. (4) University of Copenhagen, grid.5254.6, KU
  5. (5) Carnegie Observatories, grid.432988.c
  6. (6) University of Hawaii at Manoa, grid.410445.0
  7. (7) Las Campanas Observatory, grid.440392.8
  8. (8) Johns Hopkins University, grid.21107.35
  9. (9) Space Telescope Science Institute, grid.419446.a
  10. (10) University of La Serena, grid.19208.32


Eleven hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient, SSS17a, was identified in the galaxy NGC 4993. Although the gravitational wave data indicate that GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints on the nature of that system. We synthesize the optical to near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration, finding that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We conclude that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.


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Times Cited: 105

Field Citation Ratio (FCR): 48.33

Relative Citation ratio (RCR): 0.41

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