Open Access
X-ray Absorption Variability In Ngc 4507
Andrea Marinucci,Guido Risaliti,M. Elvis,Stefano Bianchi,Giorgio Matt +4 more
- Vol. 218
TLDR
In this article, the authors present a complete spectral analysis of an XMM-Newton and Chandra campaign of the obscured AGN in NGC 4507, consisting of six observations spanning a period of six months, ranging from June 2010 to December 2010.Abstract:
We present a complete spectral analysis of an XMM-Newton and Chandra campaign of the obscured AGN in NGC 4507, consisting of six observations spanning a period of six months, ranging from June 2010 to December 2010. We detect strong absorption variability on time scales between 1.5 and 4 months, suggesting that the obscuring material consists of gas clouds at parsec-scale distance. The lack of significant variability on shorter time scales suggests that this event is not due to absorption by broad line region clouds, which was instead found in other studies of similar sources. This shows that a single, universal structure of the absorber (either BLR clouds, or the parsec-scale torus) is not enough to reproduce the observed complexity of the X-ray absorption features of this AGN.read more
Citations
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Journal ArticleDOI
Evidence for a multizone warm absorber in the XMM-Newton spectrum of Markarian 304
Enrico Piconcelli,E. Jimenez-Bailon,Matteo Guainazzi,Norbert Schartel,P. M. Rodriguez-Pascual,M. Santos-Lleo +5 more
TL;DR: In this article, a two-phase warm absorber provided an adequate parameterization of Markarian 304, a Seyfert 1 galaxy at z = 0.066, and two significant emission lines were detected at 0.57 keV and 6.4 keV, respectively.
Journal ArticleDOI
Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
TL;DR: In this paper, the absorbing column density of 25 X-ray defined Seyfert 2 galaxies was studied on timescales from months to several years, and it was shown that a significant variation of column density was observed in almost all the sources.
Peer Review
Changing-look Active Galactic Nuclei
Claudio Ricci,Benny Trakhtenbrot +1 more
TL;DR: In this paper , the authors discuss the current understanding of these two classes of changing-look AGN and discuss open questions and future prospects, as well as the current state of the art.
References
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