paper

A Challenge to Identify an Optical Counterpart of the Gravitational Wave Event GW151226 with Hyper Suprime-Cam

arXiv:1710.00127 · doi:10.1093/pasj/psx125

Abstract

We present the results of the detailed analysis of an optical imaging survey conducted using the Subaru / Hyper Suprime-Cam (HSC), which aims to identify an optical counterpart to the gravitational wave event GW151226. In half a night, the - and -band imaging survey by HSC covers 63.5deg of the error region, which contains about 7\% of the LIGO localization probability, and the same field is observed in three different epochs. The detectable magnitude of the candidates in a differenced image is evaluated as mag for the requirement of at least two 5 detections, and 1744 candidates are discovered. Assuming a kilonova as an optical counterpart, we compared the optical properties of the candidates with model predictions. A red and rapidly declining light curve condition enables the discrimination of a kilonova from other transients, and a small number of candidates satisfy this condition. The presence of stellar-like counterparts in the reference frame suggests that the surviving candidates are likely to be flare stars. The fact that most of those candidates are in galactic plane, , supports this interpretation. We also checked whether the candidates are associated with the nearby GLADE galaxies, which reduces the number of contaminants even with a looser color cut. When a better probability map (with localization accuracy of ) is available, kilonova searches of up to approximately Mpc will become feasible by conducting immediate follow-up observations with an interval of 3--6 days.

arXiv comment13 pages, 10 figures, Submitted to PASJ on 12 Aug 2017

References in corpus (44)

Cited by in corpus (10)