1996/06/19 by K. A. Pounds, W. N. Brandt, Pounds, K. A. +1
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9606118
10 pages, uuencoded compressed postscript, to appear in "X-ray Imaging and Spectroscopy of Cosmic Hot Plasmas", Tokyo, March 1996
arxiv created 1996/06/19 · openalex publication_date 1996/06/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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.