Volume 444, Number 1, December II 2005
|Page(s)||119 - 132|
|Published online||21 November 2005|
X-ray obscuration and obscured AGN in the local universe
XMM-Newton Science Operations Center, European Space Astronomy Center, ESA, Apartado 50727, 28080 Madrid, Spain e-mail: email@example.com
2 Università degli Studi “Roma Tre”, Via della Vasca Navale 84, 00146, Roma, Italy
Accepted: 4 August 2005
We discuss the X-ray properties of 49 local () Seyfert 2 galaxies with HST/WFC2 high-resolution optical coverage. It includes the results of 26 still unpublished Chandra and XMM-Newton observations, which yield 25 (22) new X-ray detections in the 0.5–2 keV (2–10 keV) energy band. Our sample covers a range in the 2–10 keV observed flux, F2-10, from to erg cm-2 s-1. The percentage of objects that are likely obscured by Compton-thick matter (column density, cm-2) is 50%, and reaches 80% for . Hence, Kα fluorescent iron lines with large Equivalent Width ( keV) are common in our sample (6 new detections at a confidence level ≥2σ). They are explained as due to reflection off the illuminated side of optically thick material. We confirm a correlation between the presence of a ~100-pc scale nuclear dust in the WFC2 images and Compton-thin obscuration. We interpret this correlation as due to the large covering fraction of gas associated with the dust lanes. The X-ray spectra of highly obscured AGN invariably present a prominent soft excess emission above the extrapolation of the hard X-ray component. This soft component can account for a very large fraction of the overall X-ray energy budget. As this component is generally unobscured – and therefore likely produced in extended gas structures – it may lead to a severe underestimation of the nuclear obscuration in absorbed AGN, if standard X-ray colors are used to classify them. As a by-product of our study, we report the discovery of a soft X-ray, luminous (7 erg s-1) halo embedding the interacting galaxy pair Mkn 266.
Key words: galaxies: active / galaxies: nucleus / galaxies: Seyfert / X-ray: galaxies
© ESO, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.