UPPER LIMITS on the RATES of BINARY NEUTRON STAR and NEUTRON STAR-BLACK HOLE MERGERS from ADVANCED LIGO'S FIRST OBSERVING RUN

We report here the non-detection of gravitational wavesfrom the merger of binary– neutron starsystems and neutron star– black holesystems during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory( LIGO). In particular, we searched for gravitational-wavesignals from binary– neutron starsystems with component masses $\in [1,3]\,{M}_{\odot }$ and component dimensionless spins <0.05. We also searched for neutron star– black holesystems with the same neutron starparameters, black holemass $\in [2,99]\,{M}_{\odot }$, and no restriction on the black holespin magnitude. We assess the sensitivity of the two LIGOdetectors to these systems and find that they could have detected the merger of binary– neutron starsystems with component mass distributions of 1.35 ± 0.13 M ⊙ at a volume-weighted average distance of ~70 Mpc, and for neutron star– black holesystems with neutron starmasses of 1.4 M ⊙ and black holemasses of at least 5 M ⊙, a volume-weighted average distance of at least ~110 Mpc. From this we constrain with 90% confidence the merger rate to be less than 12,600 Gpc−3 yr−1 for binary– neutron starsystems and less than 3600 Gpc−3 yr−1 for neutron star– black holesystems. We discuss the astrophysical implications of these results, which we find to be in conflict with only the most optimistic predictions. However, we find that if no detection of neutron star–binary mergers is made in the next two Advanced LIGOand Advanced Virgo observing runs we would place significant constraints on the merger rates. Finally, assuming a rate of ${10}_{-7}^{+20}$ Gpc−3 yr−1, short gamma-ray burstsbeamed toward the Earth, and assuming that all short gamma-ray burstshave binary– neutron star( neutron star– black hole) progenitors, we can use our 90% confidence rate upper limits to constrain the beaming angle of the gamma-ray burstto be greater than $2\buildrel{\circ}\over{.} {3}_{-1.1}^{+1.7}$ ($4\buildrel{\circ}\over{.} {3}_{-1.9}^{+3.1}$).