H-ATLAS/GAMA and HeViCS - Dusty Early-Type Galaxies in Different
  Environments
  The Herschel Space Observatory has had a tremendous impact on the study of
extragalactic dust. Specifically, early-type galaxies (ETG) have been the focus
of several studies. In this paper we combine results from two Herschel studies
- a Virgo cluster study HeViCS and a broader, low-redshift H-ATLAS/GAMA study -
and contrast the dust and associated properties for similar mass galaxies. This
comparison is motivated by differences in results exhibited between multiple
Herschel studies of early-type galaxies. A comparison between consistent
modified blackbody derived dust mass is carried out, revealing strong
differences between the two samples in both dust mass and dust-to-stellar mass
ratio. In particular, the HeViCS sample lacks massive ETG with as high a
specific dust content as found in H-ATLAS. This is most likely connected with
the difference in environment for the two samples. We calculate nearest
neighbour environment densities in a consistent way, showing that H-ATLAS ETG
occupy sparser regions of the local Universe, whereas HeViCS ETG occupy dense
regions. This is also true for ETG that are not Herschel-detected but are in
the Virgo and GAMA parent samples. Spectral energy distributions are fit to the
panchromatic data. From these we find that in H-ATLAS the specific star
formation rate anticorrelates with stellar mass and reaches values as high as
in our Galaxy. On the other hand HeViCS ETG appear to have little star
formation. Based on the trends found here, H-ATLAS ETG are thought to have more
extended star formation histories and a younger stellar population than HeViCS
ETG.
