XMM-Newton observations of the Lockman Hole : Spectral analysis

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dc.creatorMainieri, V.
dc.creatorBergeron, J.
dc.creatorRosati, P.
dc.creatorHasinger, G.
dc.creatorLehmann, I.
dc.date2002-02-11
dc.date.accessioned2026-07-07T02:02:46Z
dc.date.available2026-07-07T02:02:46Z
dc.descriptionWe present the results of the X-ray spectral analysis of the deep survey obtained with the XMM-Newton observatory on the Lockman Hole. The X-ray data and the cumulative source counts were reported by Hasinger et al. (2001). Our sample contains 104 sources with a count limit of 70 of which 55 have redshift identification. The redshift distribution peaks at z ~ 0.8, with a strong excess of low z AGN and a deficiency of sources at z > 2 compared to population synthesis models for the X-ray background. The type 2 (obscured) AGN have weaker soft X-ray and optical fluxes. They cluster around z ~ 1. There is a clear separation between the classical/type 1 AGN and the obscured/type 2 ones in several diagnostics involving X-ray colour, X-ray flux, optical/near IR colour and optical brightness. Using the z subsample, we show that this separation between the AGN populations is a consequence of different absorption column densities. The two populations have the same average spectral index, Gamma ~ 1.9. At the 70 count detection limit, there is also a strong overlap between the two populations in hard X-ray flux and near IR brightness. These diagnostics should enable the classification of obscured/type 2 AGN very faint optically.
dc.description6 pages, 8 figures, Proc. Symnposium ``New Visions of the X-ray Universe in the XMM-Newton and Chandra Era", 26-30 November 2001, ESTEC, The Netherlands
dc.identifierhttps://arxiv.org/abs/astro-ph/0202211
dc.identifierhttp://arxiv.org/abs/astro-ph/0202211
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/4157
dc.subjectAstrophysics
dc.titleXMM-Newton observations of the Lockman Hole : Spectral analysis
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