SIMBAD references

1998A&A...339..327G - Astronomy and Astrophysics, volume 339, 327-336 (1998/11-2)

1H0419-577: a ``two-state'' soft X-ray Seyfert galaxy.

GUAINAZZI M., COMASTRI A., STIRPE G.M., BRANDT W.N., FIORE F., LEIGHLY K.M., MATT G., MOLENDI S., PUCHNAREWICZ E.M., PIRO L. and SIEMIGINOWSKA A.

Abstract (from CDS):

In 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 (Γ∼1.55) and featureless power-law is a good description of the whole 1.8-40keV 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 An analysis of a still unpublished ROSAT observation of the same target reveals that the soft X-ray spectrum has undergone a transition from a steep (Γ=2.5) to a flat (Γ= 1.55) state, at least in the 0.7-2keV 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.

Abstract Copyright:

Journal keyword(s): X-rays: galaxies - galaxies: Seyfert - galaxies: individual: 1H 0419-577

Simbad objects: 7

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