Enhanced Star Formation Activity of Extreme Jellyfish Galaxies in
  Massive Clusters and the Role of Ram Pressure Stripping
  Jellyfish galaxies are an excellent tool to investigate the short-term
effects of ram pressure stripping (RPS) on star formation in cluster
environments. It has been thought that the star formation activity of jellyfish
galaxies may depend on the host cluster properties, but previous studies have
not yet found a clear correlation. In this study, we estimate the \Ha-based
star formation rates (SFRs) of five jellyfish galaxies in massive clusters
($\sigma_{v, {\rm cl}}\gtrsim1000~{\rm km~s^{-1}}$) at $z\sim0.3-0.4$ using
Gemini GMOS/IFU observations to explore the relationship. Combining our results
with those in the literature, we find that the star formation activity of
jellyfish galaxies shows a positive correlation with their host cluster
velocity dispersion as a proxy of cluster mass and dynamical states. We divide
the jellyfish galaxy sample into two groups with strong and weak RPS signatures
using a morphological class. In the phase-space diagram, the jellyfish galaxies
with strong RPS features show a higher SFR and a stronger central concentration
than those with weak RPS features. We estimate their SFR excess relative to the
star formation main sequence (starburstiness; $R_{\rm SB}={\rm
SFR/SFR_{MS}}(z)$) and the density of the surrounding intracluster medium (ICM)
using scaling relations with the cluster velocity dispersion. As a result, the
starburstiness of jellyfish galaxies with strong RPS signatures clearly
exhibits positive correlations with cluster velocity dispersion, ICM density,
and strength of ram pressure. This shows that the relation between RPS and star
formation activity of jellyfish galaxies depends on the host cluster properties
and strength of ram pressure.
