1998/11/03 by Stefanie Komossa, S. Komossa, Komossa, Stefanie
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/9811049
6 pages, 2 figures (needs aaspp4.sty); to appear in the proceedings of "The First XMM Workshop" (Noordwijk, Sept 30 - Oct 2, 1998)
arxiv created 1998/11/03 · openalex publication_date 1998/11/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Warm absorbers are an important new probe of the central regions of active galaxies. So far, they revealed their existence mainly in the soft X-ray spectral region. In observing and modeling this component, we can learn a lot about the nature of the warm absorber itself, its relation to other components of the active nucleus, and the intrinsic AGN X-ray spectral shape. Here, we briefly review the basic X-ray spectral features of warm absorbers (dust-free WAs, dusty WAs, peculiar ~1.1 keV absorption, emission and reflection components) and then discuss these in more detail based on analyses of individual objects observed with the X-ray satellite ROSAT. The importance of XMM in improving our knowledge of the warm material is discussed.