Variability Studies Of CGRaBS Candidate Blazars With The OVRO 40 m Telescope At 15 GHz In Support Of Fermi

Monitoring of 1200 sources taken from the Candidate Gamma-Ray Blazar Survey (CGRaBS) has been carried out with the Owens Valley Radio Observatory 40 m telescope since mid 2007. This work is being carried out in support of Fermi Gamma-ray Space Telescope. Most of the sources are being observed every 2 days and many of them daily (see poster by Richards et al for details on the data set and reduction). Using these radio light curves it is possible to obtain information about the character of the variability using the variability index and modulation index. The characteristic time scales for the variability are investigated via structure functions and periodogram analysis. It is expected that most of the CGRaBS sources will be associated with gamma-ray blazars detected by Fermi, which implies that for many of the radio monitored sources Fermi data will be available. The presence or absence of correlations between the radio and gamma-ray light curves will provide important information about the gamma-ray emitting regions and the mechanism responsible for the variability.