High Speed Source Localization in Searches for Gravitational Waves from Compact Object Collisions

Multi-messenger astronomy is of great interest. The localization speed of gravitational wave sources is important for the success of electromagnetic follow-up. Although current gravitational wave source localization methods take up to a few seconds, even that is not sufficient for some electromagnetic bands. Therefore, one needs a more rapid localization method even if it is less accurate. Building upon an Excess power method, we describe a new localization method for compact object collisions that produces posterior probability maps in only a few hundred milliseconds. Some accuracy is lost, with the searched sky areas being approximately $10$ times larger. We imagine this new technique playing a role in a hierarchical scheme where fast early location estimates are iteratively improved upon as better analyses complete on longer time scales.