Evolution of the X-ray luminosity function of AGN

The HEAO A1 X-ray survey has detected a large number of active galactic nuclei and quasars, as recently identified using results from the HEAO A3 experiment. The sample shows some incompleteness and is not completely identified, so these effects are taken out in the analysis by correcting the effective coverage of the survey. Preliminary analysis indicates that significant evolution can be detected in these data and that the evolution rate appears stronger than that inferred from a sample selected at lower energies.