Nuclear obscuration and scattering in Seyfert 2 galaxies

We study the relationship between gaseous absorbing column density (N-H), i nfrared colors and detectability of the broad lines in a large sample of Se yfert 2 galaxies(Sy2s). We confirm that Sy2s without polarized broad lines tend to have cooler 60 mum/25 mum colors; this correlation was previously a scribed to the effect of obscuration towards the nuclear region. We find so me evidence that Sy2s without polarized broad lines have larger absorbing c olumn density (N-H) and that a fraction of them are characterized by dust l anes crossing their nuclei. However, we find that the IR colors do not corr elate with N-H, in disagreement with the obscuration scenario. Also, Sy2s w ithout polarized broad lines follow the same radio-FIR relation as normal a nd starburst galaxies, at variance with Sy2s with polarized broad lines. Th ese results indicate that the lack of broad lines in the polarized spectrum of Sy2s is mostly due to the contribution/dilution from the host galaxy or from a circumnuclear starburst, though a lesser extent to the obscuration toward the nuclear region also plays a role.