Environmental impacts on dust temperature of star-forming galaxies in
  the local Universe
  We present infrared views of the environmental effects on the dust properties
in star-forming (SF) galaxies at z ~ 0, using the AKARI Far-Infrared Surveyor
(FIS) all-sky map and the large spectroscopic galaxy sample from Sloan Digital
Sky Survey (SDSS) Data Release 7 (DR7). We restrict the sample to those within
the redshift range of 0.05 < z < 0.07 and the stellar mass range of 9.2 <
log_10 (M_star/M_solar). We select SF galaxies based on their H_alpha
equivalent width (EW_Ha> 4 A) and emission line flux ratios. We perform
far-infrared (FIR) stacking analyses by splitting the SDSS SF galaxy sample
according to their stellar mass, specific SFR (SSFR_SDSS), and environment. We
derive total infrared luminosity (LIR) for each subsample using the average
flux densities at WIDE-S (90 micron) and WIDE-L (140 micron) bands, and then
compute IR-based SFR (SFR_IR) from L_IR. We find a mild decrease of IR- based
SSFR (SSFR_IR) amongst SF galaxies with increasing local density (~0.1-dex
level at maximum), which suggests that environmental effects do not instantly
shut down the SF activity in galaxies. We also derive average dust temperature
(T_dust) using the flux densities at 90 micron and 140 micron bands. We confirm
a strong positive correlation between T_dust and SSFR_IR, consistent with
recent studies. The most important finding of this study is that we find a
marginal trend that T_dust increases with increasing environmental galaxy
density. Although the environmental trend is much milder than the SSFR-T_dust
correlation, our results suggest that the environmental density may affect the
dust temperature in SF galaxies, and that the physical mechanism which is
responsible for this phenomenon is not necessarily specific to cluster
environments because the environmental dependence of T_dust holds down to
relatively low-density environments.
