Description
The 100m Robert C. Byrd Green Bank Telescope and the 40m Owens Valley Radio Observatory telescope have been used to conduct a 31GHz survey of 3165 known extragalactic radio sources over 143deg^2^ of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4GHz flux densities of 3-10mJy. The resulting 31GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31GHz spectral indices of these sources, we find a mean 31-1.4GHz flux ratio of 0.110+/-0.003 corresponding to a spectral index of {alpha}=-0.71+/-0.01 (S_{nu}_{prop.to}{nu}^{alpha}^); 9.0%+/-0.8% of sources have {alpha}>-0.5 and 1.2%+/-0.2% have {alpha}>0. By combining this spectral-index distribution with 1.4GHz source counts, we predict 31GHz source counts in the range 1mJy<S_31_<4mJy, N(>S_31_)=(16.7+/-1.7)deg^-2^(S_31_/1mJy)^-0.80+/-0.07^.
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