Potential Gravitational-wave and Gamma-ray Multi-messenger Candidate from Oct. 30, 2015

We present a search for binary neutron star mergers during the first observing run of Advanced LIGO that produce both gravitational-wave and gamma-ray emission similar to GW170817 and GRB 170817A. We introduce a method to detect sources that do not produce significant gravitational-wave or gamma-ray burst candidates individually. Searches of this type can increase by 70\% the detections of joint gravitational-wave and gamma-ray signals. We find one possible candidate at a false alarm rate of 1 in 13 years. If confirmed, this candidate would correspond to a merger at $187^{+99}_{-87}\,$Mpc with source-frame chirp mass of $1.30^{+0.02}_{-0.03}\,M_{\odot}$. If we assume the viewing angle must be $<30^{\circ}$ to be observed by Fermi-GBM, our estimate of the distance would become $224^{+88}_{-78}\,$Mpc. By comparing the rate of binary neutron star mergers to our search-estimated rate of false alarms, we estimate that there is a 1 in 4 chance this candidate is astrophysical in origin.