FIR colours and SEDs of nearby galaxies observed with Herschel
  We present infrared colours (in the 25-500 mic spectral range) and UV to
radio continuum spectral energy distributions of a sample of 51 nearby galaxies
observed with SPIRE on Herschel. The observed sample includes all morphological
classes, from quiescent ellipticals to active starbursts. Active galaxies have
warmer colour temperatures than normal spirals. In ellipticals hosting a radio
galaxy, the far-infrared (FIR) emission is dominated bynthe synchrotron nuclear
emission. The colour temperature of the cold dust is higher in quiescent E-S0a
than in star-forming systems probably because of the different nature of their
dust heating sources (evolved stellar populations, X-ray, fast electrons) and
dust grain properties. In contrast to the colour temperature of the warm dust,
the f350/f500 index sensitive to the cold dust decreases with star formation
and increases with metallicity, suggesting an overabundance of cold dust or an
emissivity parameter beta<2 in low metallicity, active systems.
