[O III]lambda 5007, near-IR and X-ray properties of Seyfert 2 galaxies

It is known that hard X-rays (2-10 keV) are a good indicator of the intrinsic luminosity of Seyfert 2 galaxies for those cases where they are transmitted through the torus, rather than seen purely by reflection, e.g., NGC 1068. It has recently been demonstrated that the [O III]lambda 5007 emission line and hard X-ray fluxes in Seyfert 2 galaxies follow the same correlation as found for Seyfert 1 galaxies, and hence that [O III]lambda 5007 emission line fluxes can also be used to infer the intrinsic power in AGNs, Recent theoretical models predict that the inner regions of the torus have hot dust with a blackbody peak around 3.5 mu m (L band). We use comparisons of the hard X-ray, [O III]lambda 5007 and small-aperture L-band properties of low-redshift PG quasars, Seyfert 1 and 2 galaxies to infer the amount of reddening in the latter. The L band versus [O III]lambda 5007 and L band versus hard X-rays correlations found for unobscured objects (Seyfert 1 and PG quasars) allow us to estimate the torus-induced reddening in those obscured galaxies. Our values for the visual extinctions are compared with those values inferred from the hard X-ray column densities, In general we find a tendency for Seyfert 2 galaxies to have lower IR extinctions than those derived from the hard X-ray column densities, but they are nevertheless correlated in the sense that those Seyfert 2s with high column densities also display significant IR extinctions, Reddenings deduced using the small-aperture L-band data range from negligible A(V) up to 80 mag.