A DECAM SEARCH FOR AN OPTICAL COUNTERPART TO THE LIGO GRAVITATIONAL-WAVE EVENT GW151226 Academic Article uri icon

abstract

  • ABSTRACT We report the results of a Dark Energy Camera optical follow-up of the gravitational-wave (GW) event GW151226, discovered by the Advanced Laser Interferometer Gravitational-wave Observatory detectors. Our observations cover 28.8 deg2 of the localization region in the i and z bands (containing 3% of the BAYESTAR localization probability), starting 10 hr after the event was announced and spanning four epochs at 224 days after the GW detection. We achieve 5 point-source limiting magnitudes of i 21.7 and z 21.5 , with a scatter of 0.4 mag, in our difference images. Given the two-day delay, we search this area for a rapidly declining optical counterpart with 3 significance steady decline between the first and final observations. We recover four sources that pass our selection criteria, of which three are cataloged active galactic nuclei. The fourth source is offset by 5.8 arcsec from the center of a galaxy at a distance of 187 Mpc, exhibits a rapid decline by 0.5 mag over 4 days, and has a red color of i z 0.3 mag. These properties could satisfy a set of cuts designed to identify kilonovae. However, this source was detected several times, starting 94 days prior to GW151226, in the Pan-STARRS Survey for Transients (dubbed as PS15cdi) and is therefore unrelated to the GW event. Given its long-term behavior, PS15cdi is likely a Type IIP supernova that transitioned out of its plateau phase during our observations, mimicking a kilonova-like behavior. We comment on the implications of this detection for contamination in future optical follow-up observations.

published proceedings

  • ASTROPHYSICAL JOURNAL LETTERS

altmetric score

  • 21.08

author list (cited authors)

  • Cowperthwaite, P. S., Berger, E., Soares-Santos, M., Annis, J., Brout, D., Brown, D. A., ... Weller, J.

citation count

  • 41

complete list of authors

  • Cowperthwaite, PS||Berger, E||Soares-Santos, M||Annis, J||Brout, D||Brown, DA||Buckley-Geer, E||Cenko, SB||Chen, HY||Chornock, R||Diehl, HT||Doctor, Z||Drlica-Wagner, A||Drout, MR||Farr, B||Finley, DA||Foley, RJ||Fong, W||Fox, DB||Frieman, J||Garcia-Bellido, J||Gill, MSS||Gruendl, RA||Herner, K||Holz, DE||Kasen, D||Kessler, R||Lin, H||Margutti, R||Marriner, J||Matheson, T||Metzger, BD||Neilsen, EH Jr||Quataert, E||Rest, A||Sako, M||Scolnic, D||Smith, N||Sobreira, F||Strampelli, GM||Villar, VA||Walker, AR||Wester, W||Williams, PKG||Yanny, B||Abbott, TMC||Abdalla, FB||Allam, S||Armstrong, R||Bechtol, K||Benoit-Levy, A||Bertin, E||Brooks, D||Burke, DL||Carnero Rosell, A||Kind, M Carrasco||Carretero, J||Castander, FJ||Cunha, CE||D'Andrea, CB||da Costa, LN||Desai, S||Dietrich, JP||Evrard, AE||Fausti Neto, A||Fosalba, P||Gerdes, DW||Giannantonio, T||Goldstein, DA||Gruen, D||Gutierrez, G||Honscheid, K||James, DJ||Johnson, MWG||Johnson, MD||Krause, E||Kuehn, K||Kuropatkin, N||Lima, M||Maia, MAG||Marshall, JL||Menanteau, F||Miquel, R||Mohr, JJ||Nichol, RC||Nord, B||Ogando, R||Plazas, AA||Reil, K||Romer, AK||Sanchez, E||Scarpine, V||Sevilla-Noarbe, I||Smith, RC||Suchyta, E||Tarle, G||Thomas, D||Thomas, RC||Tucker, DL||Weller, J

publication date

  • August 2016