The Redshift Distribution of Infrared-Faint Radio Sources
  Infrared-Faint Radio Sources (IFRSs) are an important class of high-redshift
active galaxy, and potentially important as a means of discovering more
high-redshift radio sources, but only 25 IFRSs had redshifts prior to this
paper. Here we increase the number of IFRSs with known spectroscopic redshifts
by a factor of about 5 to 131, with redshifts up to z=4.387, and a median
redshift of z = 2.68. The IFRS redshift distribution overlaps with the high-z
radio galaxy (HzRG) redshift distribution but is significantly narrower,
suggesting that the IFRSs are a subset of the larger class of HzRGs. We also
confirm and measure the proposed correlation between redshift and 3.6 $\mu$m
flux density, making it possible to use this correlation to find even higher
redshift radio sources. Many more high-redshift sources are probably present in
existing radio survey catalogues.
