The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck

Journal Article · Fri Oct 20 04:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA8EDF· OSTI ID:22654366

Valenti, Stefano; Yang, Sheng; Tartaglia, Leonardo ^[1]; Sand, David J. ^[2]; Cappellaro, Enrico ^[3]; Corsi, Alessandra ^[4]; Jha, Saurabh W. ^[5]; Reichart, Daniel E.; Haislip, Joshua; Kouprianov, Vladimir ^[6]

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1. Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270 (United States)
2. Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721-0065 (United States)
3. INAF Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy)
4. Physics and Astronomy Department, Texas Tech University, Lubbock, TX 79409 (United States)
5. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States)
6. Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)

During the second observing run of the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with a binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by a coincident short gamma-ray burst trigger detected by the Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations of a sample of galaxies regularly monitored by the survey that fell within the combined LIGO+Virgo localization region and the larger Fermi gamma-ray burst error box. Here we report the discovery of a new optical transient (DLT17ck, also known as SSS17a; it has also been registered as AT 2017gfo) spatially and temporally coincident with GW170817. The photometric and spectroscopic evolution of DLT17ck is unique, with an absolute peak magnitude of M {sub r} = −15.8 ± 0.1 and an r -band decline rate of 1.1 mag day{sup −1}. This fast evolution is generically consistent with kilonova models, which have been predicted as the optical counterpart to binary neutron star coalescences. Analysis of archival DLT40 data does not show any sign of transient activity at the location of DLT17ck down to r ∼ 19 mag in the time period between 8 months and 21 days prior to GW170817. This discovery represents the beginning of a new era for multi-messenger astronomy, opening a new path by which to study and understand binary neutron star coalescences, short gamma-ray bursts, and their optical counterparts.

• OSTI ID: 22654366
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 848; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
COALESCENCE
COSMIC GAMMA BURSTS
EVOLUTION
GALAXIES
GAMMA RADIATION
GRAVITATIONAL WAVES
INTERFEROMETERS
NEUTRON STARS
SATELLITES