The X-ray spectrum and variability of active galaxies

Abstract

Spectra have been obtained with the use of the M. S. S. L. proportional counter system, experiment C on board Ariel 5, for 13 X-ray sources for which identifications as active galaxies seem to be reasonably sound. The data for 12 of these sources are presented here. Spectra have been obtained at different epochs for the sources NGC 5128 and NGC 4151. These data indicate that for both of these sources not only intensity variability has been observed, but also changes in the line of sight hydrogen column density.