Alexander Dietz, Nickolas Fotopoulos, Leo Singer, Curt Cutler
Short GRBs are believed to originate from the coalescence of two NSs or a NS and a BH. If this scenario is correct, short GRBs will be accompanied by the emission of strong GWs, detectable by GW observatories such as LIGO and Virgo. As compared with blind, all-sky, all-time GW searches, externally triggered searches for GW counterparts to short GRBs have the advantages of both significantly reduced detection threshold due to known time and sky location and preferentially higher GW amplitude because of face-on orientation. Based on the distribution of SNR in candidate CBC events in the most recent joint LIGO--Virgo data, we find an effective sensitive volume for GRB-triggered searches that ~2 times greater than for blind searches. For NSNS systems, a jet angle of 20 degrees, and an effective gamma-ray satellite field-of-view of 10% of the sky, this doubles the number of NSNS--short GRB associations to 4% of all NSNS detections. We also investigate the power of tests for statistical excesses in lists of sub-threshold events, and show that these are unlikely to reveal a sub-threshold population until finding individual sources is already routine.
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http://arxiv.org/abs/1210.3095
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