The Phoenix radio survey: The angular correlation function

Using the Phoenix radio survey, a homogeneous survey selected at :1.4 GHz a nd covering an area of approximate to 3 deg(2), we analyse the clustering o f the sub-mJy radio population using angular correlation function analysis. Extensive simulations are carried out to investigate the significance of t he estimated angular correlation amplitudes. Our analysis show that for the S-1.4 > 0.5 mJy sub-samples the radio source distribution is anisotropic a t the 2 sigma significance level. Additionally, we estimate upper limits fo r the angular correlation amplitudes that, despite the large uncertainties, are in good agreement with the amplitude estimates for sources brighter th an 1 mJy, detected in the FIRST radio survey (Cress et al. 1997). Adopting a radio luminosity function and assuming an evolving spatial correlation fu nction of the form xi(r) = (r/r(0))(-gamma)(1 + z)(-(3+epsilon)), with the evolution parametrised by epsilon, we find an upper limit for the angular c orrelation length r(0) approximate to 9 h(-1) Mpc for S-1.4 > 0.5 mJy and g amma = 2.1. This agrees well with the value r(0) approximate to 6 - 8 h(-1) Mpc estimated from the FIRST radio survey for sources brighter than 1 mJy. Additionally, we quantify the characteristics; in tt rms of areal coverage and limiting flux density, of future deep radio surveys to yield a signifi cant correlation amplitude detection and to explore possible changes of the correlation amplitude with flux density.