SIMBAD references

We constrain the uncertainty in waiting times for detecting the first double neutron star (DNS) mergers by gravitational wave observatories. By accounting for the Poisson fluctuations in the rate density of DNS mergers and galaxy space density inhomogeneity in the local Universe, we define a detection `zone' as a region in a parameter space constrained by the DNS merger rate and two Laser Interferometer Gravitational-wave Observatory (LIGO) operation parameters: an observation horizon distance and a science run duration. Assuming a mean rate of about 80 DNS mergers per Milky Way galaxy/Myr, we find a 1/20 chance of observing a merger by an enhanced LIGO in only 1 yr of observation. The minimum waiting time and temporal zone width for an advanced LIGO sensitivity are much shorter and imply that there is a 95 per cent probability of detecting a DNS merger in less than 60 d and a 1/20 chance of a first detection in about 1 d. At the 5 per cent probability threshold for a first detection, we find that the effect of galaxy clusters on detection is smoothed out and may only influence detection rates after 5-10 yr observation time.