On The Origin Of Unidentified EGRET Gamma-Ray Sources

The identification of celestial gamma‐ray sources with astronomical objects or object classes has remained the initial and most fundamental key for understanding their physical nature. The observational characteristic of a gamma‐ray emitter and the conditions under which an astronomical object is able to produce energetic gamma‐ray emission defines the range of candidates available for source identifications. The main obstacle must be seen in the fact that a gamma‐ray source location is often imprecise, a flux history could only be established on the basis of weeks, and uncertainties in the gamma‐ray observables are considerably large. Therefore coordinated multifrequency follow‐up campaigns or spatial‐statistical methods are required to assign proper counterpart identifications. Although Active Galactic Nuclei and pulsars are uniquely identified EGRET sources, many other gamma‐ray sources still remain unidentified. I will review properties of the population and highlight the characteristics of potential ...