NGC 1068. In this picture, the maser disk is intimately connected to the inner part of the torus. It is probably made of a large number of molecular clouds connecting the torus and the outer part of the accretion disk, giving rise to a thin disk rotating in most cases in Keplerian or sub-Keplerian motion. This toy model explains the established close connection between water megamaser emission and nuclear obscuration as a geometric effect.]{}

Introduction
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There is strong evidence that a significant fraction of Active Galactic Nuclei (AGN) are mildly or heavily obscured by a large amount of gas, preventing us from detecting their nuclear emission. The study of the column density distribution among Seyfert 2 galaxies [@1999ApJ...522..157R] is a key element to understand the nature and structure of the putative toroidal reprocessor of the AGN unified model , which is responsible for many of the observed differences between type 1 and type 2 Seyfert galaxies. The most common way to study the innermost regions of obscured AGN is through their hard X-ray emission, which can penetrate even very high obscuring column densities. The *Nuclear Spectroscopic Telescope Array* (*NuSTAR*) is a recent hard X-ray observatory launched in June 2012. 