Obscuring clouds playing hide-and-seek in the Active Nucleus H0557-385

Abstract

This paper reports on two XMM-Newton observations of the Seyfert 1 Galaxy H0557-385 obtained in 2006, which show the source at an historical low flux state, more than a factor of 10 lower than a previous XMM-Newton look in 2002. The low flux spectrum presents a strong Fe Kalpha line associated to a Compton reflection continuum. An additional spectral line around 6.6 keV is required to fit Kalpha emission from Fe XXV. The spectral curvature below 6 keV implies obscuration by neutral gas with a column density of 8*10^{23}cm^{-2} partially covering the primary emission, which still contributes for a few percent of the soft X-ray emission. Absorption by ionised material on the line of sight is required to fit the deep trough below 1 keV. The comparison of the two spectral states shows that the flux transition is to be ascribed entirely to intervening line-of-sight clouds with high column density.

5 pages, accepted for publication on MNRAS Letters

References in corpus (16)

• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
• The Contribution of the Obscuring Torus to the X--Ray Spectrum of Seyfert Galaxies: A Test for the Unification Model
• The first XMM-Newton slew survey catalogue: XMMSL1
• Extreme X-ray spectral variability in the Seyfert 2 Galaxy NGC 1365
• Changing look: from Compton-thick to Compton-thin, or the re-birth of fossil AGN
• Occultation measurement of the size of the X-ray emitting region in the Active Galactic Nucleus of NGC 1365
• The soft X-ray/NLR connection: a single photoionized medium?
• On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton
• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• Evidence for a multizone warm absorber in the XMM-Newton spectrum of Markarian 304
• Exploring the complex X-ray spectrum of NGC 4051
• The swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory
• The Seyfert 1 Galaxy Mrk 335 at a very low flux state: mapping the soft X-ray photoionised gas
• Obscured AGN: the hidden side of the X-ray Universe
• XMM-Newton observations of the Seyfert 1 AGN H0557-385
• BeppoSAX observations of Seyfert 1s in the Piccinotti sample I: poorly studied sources

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• The subarcsecond mid-infrared view of local active galactic nuclei: I. The N- and Q-band imaging atlas
• Warm absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies: I. A global view and frequency of occurrence of warm absorbers
• Are X-ray Emitting Coronae around Super Massive Black Holes Outflowing?
• The soft X-ray excess: NLS1s vs. BLS1s
• Anatomy of the AGN in NGC 5548 VIII. XMM-Newton's EPIC detailed view of an unexpected variable multilayer absorber
• Probing variability patterns of the Fe K line complex in bright nearby AGNs
• Modelling the X-ray polarimetric signatures of complex geometry: the case study of the "changing look" AGN NGC 1365
• Simultaneous XMM-\textit{Newton} and HST-COS observation of 1H0419-577: II. Broadband spectral modeling of a variable Seyfert galaxy
• Statistical Properties of Thermal Sunyaev-Zel'dovich Maps
• Absorption at the dust sublimation radius and the dichotomy between X-ray and optical classification in the Seyfert galaxy H0557-385
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• X-Ray Spectral Parameters for a Sample of 95 Active Galactic Nuclei
• Short time-scale X-ray spectral variability in the Seyfert 1 galaxy NGC 3783
• Coordinated X-ray and UV absorption within the accretion disk wind of the active galactic nucleus PG 1126-041