Deconstructing Mid-Infrared Emission Sources in Active Galactic Nuclei

Some of the energy produced by black hole accretion in active galactic nuclei (AGN) is absorbed by surrounding dust. This emission is then re-emitted at infrared (IR) wavelengths. Detailed examination of this IR emission argues the existence of a geometrically and optically thick torus of gas and dust with sizes up to ~10s pc. The torus is the main component of the obscuration of the central engine from some lines of sight. However, recent interferometric observations have found that, for some AGN, the majority of Mid-IR emission arises in a region perpendicular to the torus within the central several pc. This perpendicular emission can also be detected up to100s pc, coincident with the narrow line-emitting region (NLR) and ionization cones. In order to characterize IR emission on hundred-pc scales, we have constructed the 5-500 μm spectral energy distributions (SEDs) of a sample of AGN using new and archival data from SOFIA, as well as archival data from Herschel and Spitzer. We found that the SEDs of AGN with known extension along the NLR axis tend to peak at shorter wavelengths (~73 μm) than the SEDs of the remainder of our sample (~100 μm).