Measuring the Total Ultraviolet Light from Galaxy Clusters at z=0.5-1.6:
  The Balance of Obscured and Unobscured Star-Formation
  Combined observations from UV to IR wavelengths are necessary to fully
account for the star-formation in galaxy clusters. Low mass (log M/Msun<10)
galaxies are typically not individualy detected, particularly at higher
redshifts (z~1-2) where galaxy clusters are undergoing rapid transitions from
hosting mostly active, dust-obscured star-forming galaxies to quiescent,
passive galaxies. To account for these undetected galaxies, we measure the
total light emerging from GALEX/NUV stacks of galaxy clusters between
z=0.5-1.6. Combined with existing measurements from Spitzer, WISE, and
Herschel, we study the average UV through far-infrared (IR) spectral energy
distribution (SED) of clusters. From the SEDs, we measure the total stellar
mass and amount of dust-obscured and unobscured star-formation arising from all
cluster-member galaxies, including the low mass population. The relative
fraction of unobscured star-formation we observe in the UV is consistent with
what is observed in field galaxies. There is tentative evidence for lower than
expected unobscured star-formation at z~0.5, which may arise from rapid
redshift evolution in the low mass quenching efficiency in clusters reported by
other studies. Finally, the GALEX data places strong constraints on derived
stellar-to-halo mass ratios at z<1 which anti-correlate with the total halo
mass, consistent with trends found from local X-ray observations of clusters.
The data exhibit steeper slopes than implementations of the cluster
star-formation efficiency in semi-analytical models.
