A deep look at the nuclear region of UGC 5101 through high angular
  resolution mid-IR data with GTC/CanariCam
  We present an analysis of the nuclear infrared (IR, 1.6 to 18 $\mu$m)
emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of
its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR
high angular resolution ($0.3-0.5$ arcsec) imaging using the Si-2 filter
($\lambda_{C}=8.7\, \mu$m) and $7.5-13$ $\mu$m spectroscopy taken with
CanariCam (CC) on the 10.4m Gran Telescopio CANARIAS. We also use archival
HST/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate
the near- and mid-IR unresolved nuclear emission by modelling the imaging data
with GALFIT. We decompose the Spitzer/IRS and CC spectra using a power-law
component, which represents the emission due to dust heated by the AGN, and a
starburst component, both affected by foreground extinction. We model the
resulting unresolved near- and mid-IR, and the starburst subtracted CC spectrum
with the CLUMPY torus models of Nenkova et al. The derived geometrical
properties of the torus, including the large covering factor and the high
foreground extinction needed to reproduce the deep $9.7\, \mu$m silicate
feature, are consistent with the lack of strong AGN signatures in the optical.
We derive an AGN bolometric luminosity $L_{bol}\sim1.9\times10^{45}\,$erg
s$^{-1}$ that is in good agreement with other estimates in the literature.
