31GHz sky survey with the SZA

From late 2005 to mid-2007, the Sunyaev-Zel'dovich Array observed 7.7deg^2^ of the sky at 31GHz to a median rms of 0.18mJy/beam. We identify 209 sources at greater than 5{sigma} significance in the 31GHz maps, ranging in flux from 0.7mJy to ~200mJy.

Archival NVSS data at 1.4GHz and observations at 5GHz with the Very Large Array are used to characterize the sources. We determine the maximum-likelihood integrated source count to be N(>S)=(27.2+/-2.5)deg^-2^x(S_mJy_)^-1.18+/-0.12^ over the flux range 0.7-15mJy. This result is significantly higher than predictions based on 1.4GHz selected samples, a discrepancy which can be explained by a small shift in the spectral index distribution for faint 1.4GHz sources.