A Systematic and Quantitative Approach to the Identification of High-Energy γ-Ray Source Populations

Abstract

A large fraction of the detections to be made by the Gamma-Ray Large Area Space Telescope (GLAST) will initially be unidentified. We argue that traditional methodological approaches to identifying individuals and/or populations of γ-ray sources will encounter procedural limitations. These limitations will hamper our ability to classify source populations lying in the anticipated data set with the required degree of confidence, particularly those for which no member has yet been convincingly detected in the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO). Here we suggest a new paradigm for achieving the classification of γ-ray source populations based on the implementation of an a priori protocol to search for theoretically motivated candidate sources. In order to protect the discovery potential of the sample, it is essential that such a paradigm be defined before the data are revealed. Key to the new procedure is a statistical assessment by which the discovery of a new population can be claimed. Although we explicitly refer here to the case of GLAST, the scheme we present may be adapted to other experiments that are confronted with a similar problematic.