The fraction of bolometric luminosity absorbed by dust in DustPedia
  galaxies
  We study the fraction of stellar radiation absorbed by dust, f_abs, in 814
galaxies of different morphological types. The targets constitute the vast
majority (93%) of the DustPedia sample, including almost all large (optical
diameter larger than 1'), nearby (v <= 3000 km/s) galaxies observed with the
Herschel Space Observatory. For each object, we model the spectral energy
distribution from the ultraviolet to the sub-millimetre using the dedicated,
aperture-matched DustPedia photometry and the fitting code CIGALE. The value of
f_abs is obtained from the total luminosity emitted by dust and from the
bolometric luminosity, which are estimated by the fit. On average, 19% of the
stellar radiation is absorbed by dust in DustPedia galaxies. The fraction rises
to 25% if only late-type galaxies are considered. The dependence of f_abs on
morphology, showing a peak for Sb-Sc galaxies, is weak; it reflects a stronger,
yet broad, positive correlation with the bolometric luminosity, which is
identified for late-type, disk-dominated, high-specific-star-formation rate,
gas-rich objects. We find no variation of f_abs with inclination, at odds with
radiative transfer models of edge-on galaxies. These results call for a
self-consistent modelling of the evolution of the dust mass and geometry along
the build-up of the stellar content. We also provide template spectral energy
distributions in bins of morphology and luminosity and study the variation of
f_abs with stellar mass and specific star formation rate. We confirm that the
local Universe is missing the high f_abs}, luminous and actively star-forming
objects necessary to explain the energy budget in observations of the
extragalactic background light.
