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We present an X-ray spectroscopic study of optically selected (SDSS) Seyfert2 (Sy2) galaxies. The goal is to study the obscuration of Sy2 galaxies beyondthe local universe, using good quality X-ray spectra in combination with highS/N optical spectra for their robust classification. We analyzed all availableXMM-Newton archival observations of narrow emission line galaxies that meet theabove criteria in the redshift range 0.05<z<0.35. We initially selected narrowline AGN using the SDSS optical spectra and the BPT classification diagram. Wefurther modeled and removed the stellar continuum, and we analyzed the residualemission line spectrum to exclude any possible intermediate-type Seyferts. Ourfinal catalog comprises 31 Sy2 galaxies with median redshift z~0.1. X-rayspectroscopy is performed using the available X-ray spectra from the 3XMM andthe XMMFITCAT catalogs. Implementing various indicators of obscuration, we findseven (~23%) Compton-thick AGN. The X-ray spectroscopic Compton-thickclassification agrees with other commonly used diagnostics, such as the X-rayto mid-IR luminosity ratio and the X-ray to [OIII] luminosity ratio. Mostimportantly, we find four (~13%) unobscured Sy2 galaxies, at odds with thesimplest unification model. Their accretion rates are significantly lower thanthe rest of our Sy2 sample, in agreement with previous studies that predict theabsence of the broad line region below a certain Eddington ratio threshold.

The XMM spectral catalog of SDSS optically selected Seyfert 2 galaxies