Steep Spectrum Seyfert Galaxies

Abstract

Seyfert-type AGN that exhibit unusually strong and steep soft X-ray spectra are reviewed, building on observations made during the ROSAT all-sky survey. Two individual cases are described in brief detail, both being identified initially in the small sample of Seyferts detected in the Wide Field Camera (WFC) survey. In one case the similarity in X-ray appearance to a high state Galactic Black Hole Candidate (GBHC) is noted, while the flare-like nature of the second example could represent a detection of the stellar capture process or a major accretion disc instability. Extending the review to include the larger (and growing) sample of steep spectrum Seyfert-type galaxies being found with the ROSAT PSPC, we draw attention to the more common properties of the group, namely steep spectra, rapid variability, strong Fe II emission and identification with narrow-line Seyfert 1 galaxies.