Spectroscopic redshifts of galaxies within the Frontier Fields
  We present a catalog of 1921 spectroscopic redshifts measured in the fields
of the massive galaxy clusters MACSJ0416.1--2403 ($z=0.397$), MACSJ0717.5+3745
($z=0.546$), and MACSJ1149.5+2223 ($z=0.544$), i.e., three of the four clusters
selected by STScI as the targets of the Frontier Fields (FF) initiative for
studies of the distant Universe via gravitational lensing. Compiled in the
course of the MACS project (Massive Cluster Survey) that detected the FF
clusters, this catalog is provided to the community for three purposes: (1) to
allow the identification of cluster members for studies of the galaxy
population of these extreme systems, (2) to facilitate the removal of unlensed
galaxies and thus reduce shear dilution in weak-lensing analyses, and (3) to
improve the calibration of photometric redshifts based on both ground- and
spacebased observations of the FF clusters.
