The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarf galaxies in
  a cluster environment
  To assess the effects of the cluster environment on the different components
of the interstellar medium, we analyse the FIR-submm properties of a sample of
star-forming dwarf (SFD) galaxies detected by the Herschel Virgo Cluster Survey
(HeViCS). We determine dust masses and dust temperatures by fitting a modified
black body (MBB) function to the spectral energy distributions (SEDs). Stellar
and gas masses, star formation rates (SFRs), and metallicities are obtained
from the analysis of a set of ancillary data. Dust is detected in 49 out of 140
optically identified dwarfs covered by the HeViCS field; considering only
dwarfs brighter than $m_B$ = 18 mag, this gives a detection rate of 43%. After
evaluating different emissivity indices, we find that the FIR-submm SEDs are
best-fit by $\beta$=1.5, with a median dust temperature $T_d$ = 22.4 K.
Assuming $\beta$=1.5, 67% of the 23 galaxies detected in all five Herschel
bands show emission at 500 $\mu$m in excess of the MBB model. The excess is
inversely correlated with SFR and stellar masses. To study the variations in
the global properties of our sample due to environmental effects, we compare
the Virgo SFDs to other Herschel surveys, such as KINGFISH, the Dwarf Galaxy
Survey (DGS), and the HeViCS bright galaxy catalogue (BGC). We explore the
relations between stellar mass and HI fraction, specific SFR, dust fraction,
gas-to-dust ratio over a wide range of stellar masses. Highly HI-deficient
Virgo dwarf galaxies are mostly characterised by quenched star formation
activity and lower dust fractions giving hints for dust stripping in cluster
dwarfs. However, we find that the fraction of dust removed has to be less than
that of the HI component. Since the Virgo SFDs are likely to be crossing the
cluster for the first time, a longer timescale might be necessary to strip the
more centrally concentrated dust distribution.
