Phys. Rev. X (in the press); preprint at https://arxiv.org/abs/1712.00688

Two and half years after the first detection of gravitational waves, these observations remain preciously rare. Six gravitational-wave events have been reported so far, five mergers between pairs of black holes and one between binary neutron stars. Such mergers are much more frequent though; a stellar-mass black-hole merger happens every 2–10 minutes somewhere in the Universe, and neutron-star mergers up to a few times every minute. But with current technology only a few of those can be resolved, whereas the vast majority contributes to a stochastic background.

To tap into the rich information contained in the gravitational-wave background — for example about the population properties of far-away black holes — Rory Smith and Eric Thrane developed a new method to search for unresolved events. In place of the currently used cross-correlation approach, they employ Bayesian parameter estimation. They expect that with their method the stochastic background can be determined within a day or so, whereas it takes around one year with the cross-correlation approach.