Iron line emission and variability in the X-ray spectrum of the Seyfert galaxy NGC 5548

Abstract

The MSSL spectrometer on the Ariel V satellite has detected a variable iron emission feature in the X-ray spectrum of NGC 5548. Comparison with other observations indicates that both the slope and intensity of the continuum spectrum are variable. It is suggested that the iron emission is due to fluorescent excitation of the gas in the broad emission-line region surrounding the X-ray emitting nucleus of the galaxy.