The soft X-ray spectrum of NGC 4151

Abstract

EXOSAT observations of the Seyfert galaxy NGC 4151 over the period July 1983 to April 1984 have revealed a decreasing flux in the 2 10 keV band. In accord with previous measurements a power law spectrum attenuated with a simple column of cold gas does not provide a satisfactory spectral fit below ∼3 keV, where a lower relative opacity is required. Inclusion of additional low energy data from the EXOSAT telescopes allows the modelling of the absorbing column to be improved and reveals a second, separate, soft X-ray spectral component.