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Title: The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South

Here, we present a near-infrared spectral sequence of the electromagnetic counterpart to the binary neutron star merger GW170817 detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo. Our data set comprises seven epochs of J+H spectra taken with FLAMINGOS-2 on Gemini-South between 1.5 and 10.5 days after the merger. In the initial epoch, the spectrum is dominated by a smooth blue continuum due to a high-velocity, lanthanide-poor blue kilonova component. Starting the following night, all of the subsequent spectra instead show features that are similar to those predicted in model spectra of material with a high concentration of lanthanides, including spectral peaks near 1.07 and 1.55 μm. Our fiducial model with 0.04 M ⊙ of ejecta, an ejection velocity of v = 0.1c, and a lanthanide concentration of X lan = 10 –2 provides a good match to the spectra taken in the first five days, although it over-predicts the late-time fluxes. We also explore models with multiple fitting components, in each case finding that a significant abundance of lanthanide elements is necessary to match the broad spectral peaks that we observe starting at 2.5 days after the merger. These data provide direct evidence that binary neutron star mergers are significantmore » production sites of even the heaviest r-process elements.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [5] ;  [5] ;  [2] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12] ;  [13] more »;  [14] ;  [6] ;  [9] ;  [9] ;  [14] ;  [15] ;  [16] ;  [17] ;  [7] ;  [9] ;  [18] ;  [19] « less
  1. Ohio Univ., Athens, OH (United States)
  2. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
  3. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Brandeis Univ., Waltham, MA (United States)
  5. Northwestern Univ., Evanston, IL (United States)
  6. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  7. Univ. of Pennsylvania, Philadelphia, PA (United States)
  8. Syracuse Univ., Syracuse, NY (United States)
  9. Univ. of Chicago, Chicago, IL (United States)
  10. The Observatories of the Carnegie Institution for Science, Pasadena, CA (United States)
  11. Univ. of Oregon, Eugene, OR (United States); Univ. of Chicago, Chicago, IL (United States)
  12. Univ. of California, Santa Cruz, CA (United States)
  13. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  14. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  15. Columbia Univ., New York, NY (United States)
  16. Univ. of California, Berkeley, CA (United States)
  17. Space Telescope Science Institute, Baltimore, MD (United States); The Johns Hopkins Univ., Baltimore, MD (United States)
  18. Univ. of Arizona, Tucson, AZ (United States)
  19. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Brandeis Univ., Waltham, MA (United States)
Publication Date:
Report Number(s):
arXiv:1710.05454; FERMILAB-PUB-17-497-A-AE-CD
Journal ID: ISSN 2041-8213; 1630794; TRN: US1702933
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 848; Journal Issue: 2; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; binaries: close; nuclear reactions; nucleosynthesis; abundances; stars: neutron
OSTI Identifier:
1408213