1998A&A...339..327G


Query : 1998A&A...339..327G

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 An analysis of a still unpublished ROSAT observation of the same target reveals that the soft X-ray spectrum has undergone a transition from a steep (Γ=2.5) to a flat (Γ= 1.55) state, at least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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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 LB 1727 Sy1 04 26 00.7188165240 -57 12 01.769902992 13.68 14.58 14.37 14.8   ~ 251 0
2 NGC 3227 GiP 10 23 30.5765149296 +19 51 54.282206700   12.61 11.79     ~ 1614 1
3 NGC 3783 Sy1 11 39 01.7096819040 -37 44 19.009642992   12.46 13.43 11.33 12.1 ~ 1551 0
4 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5556 1
5 Mrk 841 Sy1 15 04 01.1935384104 +10 26 15.780409692   14.50 14.27     ~ 611 0
6 NGC 6814 Sy1 19 42 40.5862186152 -10 19 25.108718844   15.33 14.21 11.7 11.3 ~ 761 0
7 Mrk 926 Sy1 23 04 43.4776098480 -08 41 08.629476864   16.20 15.91 9.4   ~ 423 0

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2022.05.24-05:21:10

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