Radio Variability Studies of Gamma-Ray Blazars with the OVRO 40 m
  Telescope
  Since late 2007, we have been monitoring a large sample of known and likely
gamma-ray-loud blazars at 15 GHz twice per week with the Owens Valley Radio
Observatory (OVRO) 40 m Telescope. Our initial sample included the 1158 sources
above declination -20 degrees from the Candidate Gamma-Ray Blazar Survey
(CGRaBS), and we have since added nearly 400 more sources, including all
blazars associated with Fermi Large Area Telescope (LAT) detections in the
First AGN Catalog (1LAC). Here, we describe the new sample and present results
for 2008 through early 2011. Using statistical likelihood analyses, we compare
the variability amplitude for various sub-populations within our sample. These
include comparisons of gamma-ray-loud versus gamma-ray-quiet objects, BL Lac
objects versus flat-spectrum radio quasars, and a study of the variability
amplitude trend with redshift. We also describe KuPol, the new digital Ku-band
receiver being constructed for the 40 m telescope. This new receiver will
provide total intensity and linear polarization measurements over the 12-18 GHz
band, with 16 MHz spectral resolution.
