Dusty Tori of Luminous Type 1 Quasars at z \sim 2
  We present Spitzer infrared spectra and ultra-violet to mid-infrared spectral
energy distributions (SEDs) of 25 luminous type 1 quasars at z \sim 2. In
general, the spectra show a bump peaking around 3 {\mu}m, and the 10 {\mu}m
silicate emission feature. The 3 {\mu}m emission is identified with hot dust
emission at its sublimation temperature. We explore two approaches to modeling
the SED: (i) using the Clumpy model SED from Nenkova et al. (2008a), and (ii)
the Clumpy model SED, and an additional blackbody component to represent the 3
{\mu}m emission. In the first case, a parameter search of \sim 1.25 million
Clumpy models shows: (i) if we ignore the UV-to-near-IR SED, models fit the 2-8
{\mu}m region well, but not the 10 {\mu}m feature; (ii) if we include the
UV-to-near-IR SED in the fit, models do not fit the 2-8 {\mu}m region. The
observed 10 {\mu}m features are broader and shallower than those in the
best-fit models in the first approach. In the second case, the shape of the 10
{\mu}m feature is better reproduced by the Clumpy models. The additional
blackbody contribution in the 2-8 {\mu}m range allows Clumpy models dominated
by cooler temperatures (T < 800K) to better fit the 8-12{\mu}m SED. A centrally
concentrated distribution of a small number of torus clouds is required in the
first case, while in the second case the clouds are more spread out radially.
The temperature of the blackbody component is ~ 1200 K as expected for graphite
grains.
