THE NUCLEAR INFRARED EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs), and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGNs; L sub(bol) 10 super(42) erg s super(-1)). Infrared (IR) observations may advance our understanding of the accretion flows in LLAGNs, the fate of the obscuring toms at low accretion rates, and, perhaps, the star formation histories of these objects. We separate the present TI AGN sample into three categories depending on their Eddington ratio and radio emission, finding different IR characteristics for each class. The nuclear SEDs of these galaxies are diverse; some resemble typical Seyfert nuclei, while others lack a well-defined MIR "dust bump." Strong silicate emission is present in many of these objects. We speculate that this, together with high ratios of silicate strength to hydrogen column density, could suggest optically thin dust and low dust-to-gas ratios, in accordance with model predictions that LLAGNs do not host a Seyfert-like obscuring torus.