Comparison of the optical and X-ray obscuration in AGN

Resumen del trabajo presentado al XXIX XMM-Newton SSC consortium meeting, celebrado en Madrid (España) del 14 al 15 de marzo de 2016.
To provide insight into the apparent mismatch between the optical and X-ray absorption properties observed in 10-30 % of Active Galactic Nuclei (AGN), we have conducted a detailed study of two X-ray unabsorbed AGN with a type-2 optical spectroscopic classification. In addition to high quality X-ray spectroscopic observations, that we used to determine both the AGN luminosities and absorption, we have a VLT/XSHOOTER UV-to-near-IR high resolution spectrum for each object, that we used to determine the AGN intrinsic emision corrected for both contamination from the AGN hosts and extinction. Thanks to the high quality data available for these two intriguing sources, we unveil the origin of the mismatch. The most likely explanation is that both objects have an intrinsically high dust-to-gas ratio. In addition, we are conducting an statistical analysis of the optical obscuration and X-ray absorption properties of 159 Type-1 AGN drawn from BUXS to determine the distribution of dust-to-gas ratios in AGN over a broad range of luminosities and redshifts.