ASCA Observations of Seyfert 1 galaxies: III. The Evidence for Absorption & Emission due to Photoionized Gas

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dc.creatorGeorge, I. M.
dc.creatorTurner, T. J.
dc.creatorNetzer, Hagai
dc.creatorNandra, K.
dc.creatorMushotzky, R. F.
dc.creatorYaqoob, T.
dc.date1997-08-05
dc.date.accessioned2026-07-07T10:48:01Z
dc.date.available2026-07-07T10:48:01Z
dc.description(Abridged) We present the results from a detailed analysis of the 0.6 - 10 keV spectra of 23 ASCA observations of 18 objects. We find that in most cases the underlying continuum can be well-represented by a powerlaw with a photon index Gamma approx 2. However we find strong evidence for photoionized gas in the line-of-sight to 13/18 objects. We present detailed modelling of this gas based upon the ION photoionization code. We find the X-ray ionization parameter for the ionized material is strongly peaked at Ux approx 0.1. The column densities of ionized material are typically in the range N_{H,z} approx 10^{21}--10^{23} cm^{-2}, although highly ionized column densities up to 10^{24} cm^{-2} cannot be excluded in some cases. We also investigate the importance of the emission-spectrum from the ionized gas, finding that it significantly improves the fit to many sources with an intensity consistent with material subtending a large solid angle at the central source. A deficit of counts is observed at approx 1 keV in the sources exhibiting the strongest absorption features. We suggest this is likely to be the signature of a second zone of (more highly) ionized gas, which might have been seen previously in the deep Fe K-shell edges observed in some Ginga observations. We find evidence that the ionized material in NGC 3227 and MCG-6-30-15 contains embedded dust, whilst there is no such evidence in the other sources
dc.descriptionAccepted for publication in ApJS, LaTeX. 12 tables & 18 figs with a grand total of 115 pages (for other download options & full abstract see http://lheawww.gsfc.nasa.gov/~george/papers/gnt_paper3/abstract.html
dc.identifierhttps://arxiv.org/abs/astro-ph/9708046
dc.identifierhttp://arxiv.org/abs/astro-ph/9708046
dc.identifierAstrophys.J.Suppl.114:73,1998
dc.identifierdoi:10.1086/313067
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/183735
dc.subjectAstrophysics
dc.titleASCA Observations of Seyfert 1 galaxies: III. The Evidence for Absorption & Emission due to Photoionized Gas
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