Absorption at the Dust Sublimation Radius and the Dichotomy Between X-ray and Optical Classification in the Seyfert Galaxy H0557-385

Coffey, D.; Longinotti, A.; Rodriguez-Ardila, A.; Guainazzi, M.; Miniutti, G.; Bianchi, S.; de la Calle, I.; Piconcelli, E.; Ballo, L.; Linares, M.
Bibliographical reference

The X-ray Universe 2014, edited by Jan-Uwe Ness. Online at http://xmm.esac.esa.int/external/xmm_science/workshops/2014symposium/, id.50

Advertised on:
7
2014
Number of authors
10
IAC number of authors
1
Citations
0
Refereed citations
0
Description
In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability from a typical unabsorbed Seyfert 1 type spectrum to a Compton-thin absorbed state on time scales of ˜ 5 years. This extreme change in spectral shape can be attributed to variations in the column density and covering fraction of a neutral absorbing medium attenuating emission from the central continuum source. Evidence for both Compton reflection and warm absorption have also been detected in the spectra. Optical spectroscopy observations concurrent with a 2010 XMM-Newton observation campaign have detected the presence of broad optical emission lines during an X-ray absorption event. From the analysis of both X-ray and optical spectroscopic data, it has been inferred that the X-ray spectral variability is a result of obscuration of the central emission region by a clumpy absorber, located outside the broad line region, which covers ≥ 80 per cent of the source with an average column density of N_{H} ˜ 7×10^{23} cm^{-2}.