An advanced analysis technique for transient searches in wide-field gamma-ray observatories

Wide-field gamma-ray telescopes typically have highly variable event-by-event resolution which leads to a number of unique and challenging analysis requirements––particularly when conducting transient searches over multiple time scales. By generalizing the ideas of the Gaussian weighting analysis to point-spread functions of arbitrary shape and the regime of Poisson statistics, an efficient analysis which uses the event-by-event resolution is developed with a sensitivity similar to that of a well-implemented maximum likelihood analysis. In this development, the effect of a number of different approximations on the sensitivity and speed of the final analysis can be easily determined and tuned to the particular application. The analysis method is particularly well suited to transient detection in wide field-of-view gamma-ray observatories, and is currently used for the 40 s–3 h transient search in the Milagro observatory.