A mid-infrared spectroscopic atlas of local active galactic nuclei on
  sub-arcsecond resolution using GTC/CanariCam
  We present an atlas of mid-infrared (mid-IR) ~7.5-13micron spectra of 45
local active galactic nuclei (AGN) obtained with CanariCam on the 10.4m Gran
Telescopio CANARIAS (GTC) as part of an ESO/GTC large program. The sample
includes Seyferts and other low luminosity AGN (LLAGN) at a median distance of
35Mpc and luminous AGN, namely PG quasars, (U)LIRGs, and radio galaxies (RG) at
a median distance of 254Mpc. To date, this is the largest mid-IR spectroscopic
catalog of local AGN at sub-arcsecond resolution (median 0.3arcsec). The goal
of this work is to give an overview of the spectroscopic properties of the
sample. The nuclear 12micron luminosities of the AGN span more than four orders
of magnitude, nu*Lnu(12micron)~ 3e41-1e46erg/s. In a simple mid-IR spectral
index vs. strength of the 9.7micron silicate feature diagram most LLAGN,
Seyfert nuclei, PG quasars, and RGs lie in the region occupied by clumpy torus
model tracks. However, the mid-IR spectra of some might include contributions
from other mechanisms. Most (U)LIRG nuclei in our sample have deeper silicate
features and flatter spectral indices than predicted by these models suggesting
deeply embedded dust heating sources and/or contribution from star formation.
The 11.3micron PAH feature is clearly detected in approximately half of the
Seyfert nuclei, LLAGN, and (U)LIRGs. While the RG, PG quasars, and (U)LIRGs in
our sample have similar nuclear 12micron luminosities, we do not detect nuclear
PAH emission in the RGs and PG quasars.
