H$\alpha$ Star Formation Rates of $z$ > 1 Galaxy Clusters in the IRAC
  Shallow Cluster Survey
  We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters
at 1.0 < $z$ < 1.5 in the IRAC Shallow Cluster Survey. We use Wide Field Camera
3 grism data to spectroscopically identify H$\alpha$ emitters in both the cores
of galaxy clusters as well as in field galaxies. We find a large
cluster-to-cluster scatter in the star formation rates within a projected
radius of 500 kpc, and many of our clusters (~60%) have significant levels of
star formation within a projected radius of 200 kpc. A stacking analysis
reveals that dust reddening in these star-forming galaxies is positively
correlated with stellar mass and may be higher in the field than the cluster at
a fixed stellar mass. This may indicate a lower amount of gas in star-forming
cluster galaxies than in the field population. Also, H$\alpha$ equivalent
widths of star-forming galaxies in the cluster environment are still suppressed
below the level of the field. This suppression is most significant for lower
mass galaxies (log M$_{*}$ < 10.0 M$_{\odot}$). We therefore conclude that
environmental effects are still important at 1.0 < $z$ < 1.5 for star-forming
galaxies in galaxy clusters with log M$_{*}$ < 10.0 M$_{\odot}$.
