1H0419-577: A "two-state" soft X-ray Seyfert galaxy

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dc.creatorGuainazzi, M.
dc.creatorComastri, A.
dc.creatorStripe, G. M.
dc.creatorBrandt, W. N.
dc.creatorFiore, F.
dc.creatorLeighly, K. M.
dc.creatorMatt, G.
dc.creatorMolendi, S.
dc.creatorPuchnarewicz, E. M.
dc.creatorPiro, L.
dc.creatorSiemiginowska, A.
dc.date1998-08-03
dc.date.accessioned2026-07-07T02:27:32Z
dc.date.available2026-07-07T02:27:32Z
dc.descriptionIn this paper we report on the first simultaneous optical and X-ray (Beppo-SAX) observations of the radio-quiet AGN 1H0419-577. The optical spectrum clearly leads us to classify this source as a Seyfert 1. The X-ray spectrum is, however, somewhat at odds with this classification: a simple flat (Gamma ~ 1.55) and featureless power--law is a good description of the whole 1.8-40 keV spectrum, even if the upper limit to a broad iron line is not very tight. An analysis of a still unpublished ROSAT observation of the same target reveals that the soft X-ray spectrum has undergone a transition from a steep (Gamma ~ 2.5) to a flat (Gamma ~ 1.55) state, at least in the 0.7-2 keV band. If this difference is due to a remarkably variable soft excess, it is unlikely that a single component is responsible for the optical/UV/soft X-ray spectral distribution. The hypothesis that the difference is due to a change in the primary X-ray continuum and its implications for current Comptonization models are discussed.
dc.description11 pages, Latex, 8 Postscript figures, accepted for publication in Astronomy and Astrophysics
dc.identifierhttps://arxiv.org/abs/astro-ph/9808009
dc.identifierhttp://arxiv.org/abs/astro-ph/9808009
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/12732
dc.subjectAstrophysics
dc.title1H0419-577: A "two-state" soft X-ray Seyfert galaxy
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