CONSISTENT ANALYSIS OF GAMMA-RAY ASTRONOMY EXPERIMENTS

A general procedure is proposed for analyzing and reporting results of gamma-ray astronomy experiments. A single set of variables is to be used for all types of experiments, to allow unambiguous comparison of instruments and results. Upper (or lower) limits to the number of counts from a source are obtained from a likelihood function. The upper limits from this method are often larger than those obtained by approximate methods previously used. An effective efficiency of detection, compensating the flux value or limit for the steep slope of the background spectrum, decouples the significance of the result from the energy threshold quoted. The observed intensity of background gamma radiation should also be reported, and source fluxes expressed as ratios to the background at the given atmospheric depth, as well as in photons (cm2·sec)-1. © 1969.