The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Discovery of the Optical Counterpart Using the Dark Energy Camera

Journal Article · Mon Oct 16 00:00:00 EDT 2017 · The Astrophysical Journal. Letters (Online)

DOI:https://doi.org/10.3847/2041-8213/aa9059· OSTI ID:1408100

Soares-Santos, M.; Holz, D. E.; Annis, J.; Chornock, R.; Herner, K.; Berger, E.; Brout, D.; Chen, H. -Y.; Kessler, R.; Sako, M.; Allam, S.; Tucker, D. L.; Butler, R. E.; Palmese, A.; Doctor, Z.; Diehl, H. T.; Frieman, J.; Yanny, B.; Lin, H.; Scolnic, D. ; Cowperthwaite, P.; Neilsen, E.; Marriner, J.; Kuropatkin, N.; Hartley, W. G.; Paz-Chinchón, F.; Alexander, K. D.; Balbinot, E.; Blanchard, P.; Brown, D. A.; Carlin, J. L.; Conselice, C.; Cook, E. R.; Drlica-Wagner, A.; Drout, M. R.; Durret, F.; Eftekhari, T.; Farr, B.; Finley, D. A.; Foley, R. J.; Fong, W.; Fryer, C. L.; García-Bellido, J.; Gill, M. S. .. S.; Gruendl, R. A.; Hanna, C.; Kasen, D.; Li, T. S.; Lopes, P. A. A.; Lourenço, A. C. C.; Margutti, R.; Marshall, J. L.; Matheson, T.; Medina, G. E.; Metzger, B. D.; Muñoz, R. R.; Muir, J.; Nicholl, M.; Quataert, E.; Rest, A.; Sauseda, M.; Schlegel, D. J.; Secco, L. F.; Sobreira, F.; Stebbins, A.; Villar, V. A.; Vivas, K.; Walker, A. R.; Wester, W.; Williams, P. K. G.; Zenteno, A.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Banerji, M.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; D’Andrea, C. B.; Costa, L. N. da; Davis, C.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gaztanaga, E.; Gerdes, D. W.; Giannantonio, T.; Goldstein, D. A.; Gruen, D.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Kent, S.; Krause, E.; Kron, R.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; McMahon, R. G.; Menanteau, F.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R. L. C.; Petravick, D.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Thomas, R. C.; Troxel, M. A.; Vikram, V.; Wechsler, R. H.; Weller, J.

Here, we present the Dark Energy Camera (DECam) discovery of the optical counterpart of the first binary neutron star merger detected through gravitational-wave emission, GW170817. Our observations commenced 10.5 hr post-merger, as soon as the localization region became accessible from Chile. We imaged 70 deg² in the i and z bands, covering 93% of the initial integrated localization probability, to a depth necessary to identify likely optical counterparts (e.g., a kilonova). At 11.4 hr post-merger we detected a bright optical transient located $$10\buildrel{\prime\prime}\over{.} 6$$ from the nucleus of NGC 4993 at redshift z = 0.0098, consistent (for $${H}_{0}=70$$ km s^–1 Mpc^–1) with the distance of 40 ± 8 Mpc reported by the LIGO Scientific Collaboration and the Virgo Collaboration (LVC). At detection the transient had magnitudes of $i=17.3$ and $z=17.4$, and thus an absolute magnitude of $${M}_{i}=-15.7$$, in the luminosity range expected for a kilonova. We identified 1500 potential transient candidates. Applying simple selection criteria aimed at rejecting background events such as supernovae, we find the transient associated with NGC 4993 as the only remaining plausible counterpart, and reject chance coincidence at the 99.5% confidence level. We therefore conclude that the optical counterpart we have identified near NGC 4993 is associated with GW170817. This discovery ushers in the era of multi-messenger astronomy with gravitational waves and demonstrates the power of DECam to identify the optical counterparts of gravitational-wave sources.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); The Ohio State Univ., Columbus, OH (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR); USDOE National Nuclear Security Administration (NNSA)
• Contributing Organization: The Dark Energy Survey and The Dark Energy Camera GW-EM Collaboration
• Grant/Contract Number: AC02-76SF00515; AC02-07CH11359; AC02-05CH11231; AC05-00OR22725; AC52-06NA25396; SC0011726
• OSTI ID: 1408100
• Alternate ID(s): OSTI ID: 1418148; OSTI ID: 1421834; OSTI ID: 1422481; OSTI ID: 1422966; OSTI ID: 1602503
• Report Number(s): FERMILAB-PUB-17-454-AE-CD-PPD; arXiv:1710.05459; LA-UR-17-29523; TRN: US1702930
• Journal Information: The Astrophysical Journal. Letters (Online), Vol. 848, Issue 2; ISSN 2041-8213
• Publisher: Institute of Physics (IOP)
• Country of Publication: United States
• Language: English

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