The Deep Swire Field. I. 20 cm Continuum Radio Observations: A Crowded Sky

We present results from deep radio observations taken with the Very Large Array at a center frequency of 1400 MHz covering a region of the Spitzer Wide-area InfraRed Extragalactic Survey of the Spitzer Legacy survey, centered at 10^h46^m00^s, 59°01'00''(J2000). The reduction and cataloging of radio sources are described. An electronic catalog of the sources detected above 5σ is also presented. The survey presented is the deepest so far in terms of the radio source density on the sky. Perhaps surprisingly, the sources down to the bottom of the catalog appear to have median angular sizes still greater than 1 arcsec, like their cousins 10-100 times stronger. The shape of the differential log N-log S counts also seems to require a correction for the finite sizes of the sources to be self-consistent. If the log N-log S normalization remains constant at the lowest flux densities, there are about six sources per square arcminute at 15 μJy at 20 cm. Given the finite-source size this implies that we may reach the natural confusion limit near 1 μJy.