Cold dust and young starbursts: spectral energy distributions of
  Herschel SPIRE sources from the HerMES survey
  We present spectral energy distributions (SEDs) for 68 Herschel sources
detected at 5-sigma at 250, 350 and 500 mu in the HerMES SWIRE-Lockman field.
We explore whether existing models for starbursts, quiescent star-forming
galaxies and for AGN dust tori are able to model the full range of SEDs
measured with Herschel. We find that while many galaxies (~ 56 %) are well
fitted with the templates used to fit IRAS, ISO and Spitzer sources, for about
half the galaxies two new templates are required: quiescent ('cirrus') models
with colder (10-20 K) dust, and a young starburst model with higher optical
depth than Arp 220. Predictions of submillimetre fluxes based on model fits to
4.5-24 mu data agree rather poorly with the observed fluxes, but the agreement
is better for fits to 4.5-70 mu data. Herschel galaxies detected at 500 mu tend
to be those with the very highest dust masses.
