The angular two-point correlation function for the first radio survey

The FIRST (Faint Images of the Radio Sky at Twenty centimeters) survey now covers 1550 deg(2) of sky, where 07(h)16 less than or similar to alpha less than or equal to 17(h)40 and 28.3 degrees less than or similar to delta less than or similar to 42 degrees. This yields a catalog of 138,665 sources above the survey threshold of 1 mJy, about one-third of which are in double-lobed and multicomponent sources. We have used these data to obtain the first high-significance measurement of the two-point angular correlation for a deep radio sample. We find that the correlation function between 0.02 degrees and 2 degrees is well fitted by a power law of the form A theta(y), where A approximate to 3 x 10(-3) and y approximate to - 1.1. On small scales (theta < 0.2 degrees), double and multicomponent sources are shown to have a larger clustering amplitude than that of the whole sample. Sources with flux densities below 2 mJy are found to have a shallower slope than that obtained for the whole sample, consistent with there being a significant contribution from starbursting galaxies at these faint fluxes. The cross-correlation of radio sources and Abell clusters is determined. A preliminary approach to inferring spatial information is outlined.