Observations of cold gas and star formation in dwarf S0 galaxies
  Very little work has been done on star formation in dwarf lenticular galaxies
(S0s). We present 2D-spectroscopic and millimetre observations made by Centro
Astronomico Hispano Aleman (CAHA) 3.5 m optical and the IRAM-30 m millimetre
telescopes, respectively, for a sample of four dwarf S0 galaxies with multiple
star formation regions in the field environment. We find that although most of
the sources deviate from the star forming main sequence relation, they all
follow the Kennicutt-Schmidt law. After comparing the stellar and Halpha
kinematics, we find that the velocity fields of both stars and ionized gas do
not show regular motion and the velocity dispersions of stars and ionized gas
are low in the regions with high star formation, suggesting these star-forming
S0 galaxies still have significant rotation. This view can be supported by the
result that most of these dwarf S0 galaxies are classified as fast rotators.
The ratio of average atomic gas mass to stellar mass (~ 47%) is much greater
than that of molecular gas mass to stellar mass (~ 1%). In addition, the
gas-phase metallicities in the star-forming regions are lower than that of the
non-star-forming regions. These results indicate that the extended star
formation may originate from the combination of abundant atomic hydrogen, long
dynamic time scale and low-density environment.
