Obscuration in active galactic nuclei: near-infrared luminosity relations and dust colors

We combine two approaches to isolate the AGN luminosity at near-IR wavelengths and relate the near-IR pure AGN luminosity to other tracers of the AGN. Using integral-field spectroscopic data of an archival sample of 51 local AGNs, we estimate the fraction of non-stellar light by comparing the nuclear equivalent width of the stellar 2.3 m CO absorption feature with the intrinsic value for each galaxy. We compare this fraction to that derived from a spectral decomposition of the integrated light in the central arcsecond and find them to be consistent with each other. Using our estimates of the near-IR AGN light, we find a strong correlation with presumably isotropic AGN tracers. We show that a significant o set exists between type 1 and type 2 sources in the sense that type 1 sources are 7 (10) times brighter in the near-IR at logL MIR = 42.5 (logL X = 42.5). These o sets only become clear when treating infrared type 1 sources as type 1 AGNs. All AGNs have very red near- to mid-IR dust colors. This, as well as the range of observed near-IR temperatures, can be explained with a simple model with only two free parameters: the obscuration to the hot dust and the ratio between the warm and hot dust areas. We find obscurations of A hot = 5::: 15 mag for infrared type 1 sources and A hot = 15::: 35 mag for type 2 sources. The ratio of hot dust to warm dust areas of about 1000 is nicely consistent with the ratio of radii of the respective regions as found by infrared interferometry.