The recent discovery of the first four afterglows of short-hard gamma-ray bursts ( SHBs ) , and the properties inferred for these bursts – as well as for four other SHBs with known or constrained redshift – suggests that these events typically result from long-lived progenitor systems .
The most popular model invokes the merger of two compact objects , either double neutron star ( DNS ) binaries or neutron star-black hole ( NS-BH ) systems .
Such events should emit a significant fraction of their ultimate binding energy in gravitational radiation in the frequency range that is accessible to current and next-generation ground-based gravitational-wave observatories .
In this work we combine the census of SHB observations with refined theoretical analysis to perform a critical evaluation of the compact binary model .
We then explore the implications for gravitational wave detection of these events .
Beginning from the measured star-formation rate through cosmic time , we consider what intrinsic luminosity and lifetime distributions can reproduce both the known SHB redshifts and luminosities as well as the peak flux distribution of the large BATSE SHB sample .
We find that : ( 1 ) The typical progenitor lifetime , \tau _ { * } , is long .
Assuming lognormal lifetime distribution \tau _ { * } > 4 [ 1 ] Gyr ( at 2 [ 3 ] \sigma c.l . ) .
If the lifetime distribution is a power-law with index \eta then \eta > -0.5 [ -1 ] ( at 2 [ 3 ] \sigma c.l . ) .
This result is difficult to reconcile with the properties of the observed galactic DNS population , suggesting that if SHBs do result from DNS mergers then the observed galactic binaries do not represent the cosmic DNS population .
( 2 ) We find that the local rate of SHBs is at least { \cal R } _ { SHB } \gtrsim 10 ~ { } Gpc ^ { -3 ~ { } } yr ^ { -1 } and may be higher by several orders of magnitude , significantly above previous estimates .
( 3 ) We find that , assuming that SHBs do result from compact binaries , our predictions for the LIGO and VIRGO event rates are encouraging : The chance for detection by current facilities is not negligible , while a coincident observation of electromagnetic and gravitational radiation from an SHB is guaranteed for next-generation observatories .