Dual Effects of Ram Pressure on Star Formation in Multi-phase Disk
  Galaxies with Strong Stellar Feedback
  We investigate the impact of ram pressure stripping due to the intracluster
medium (ICM) on star-forming disk galaxies with a multi-phase interstellar
medium (ISM) maintained by strong stellar feedback. We carry out
radiation-hydrodynamics simulations of an isolated disk galaxy embedded in a
10^11 Msun dark matter halo with various ICM winds mimicking the cluster
outskirts (moderate) and the central environment (strong). We find that both
star formation quenching and triggering occur in ram pressure-stripped
galaxies, depending on the strength of the winds. HI and H$_2$ in the outer
galactic disk are significantly stripped in the presence of the moderate winds,
whereas turbulent pressure provides support against ram pressure in the central
region where star formation is active. Moderate ICM winds facilitate gas
collapsing, increasing the total star formation rates by ~40% when the wind is
oriented face-on or ~80% when it is edge-on. In contrast, strong winds rapidly
blow away neutral and molecular hydrogen gas from the galaxy, suppressing the
star formation by a factor of two within ~200 Myr. Dense gas clumps with N_H >
10 Msun pc^-2 are easily identified in extraplanar regions, but no significant
young stellar populations are found in such clumps. In our attempts to enhance
radiative cooling by adopting a colder ICM of T=10^6K, only a few additional
stars are formed in the tail region, even if the amount of newly cooled gas
increases by an order of magnitude.
