Ultra-high energy cosmic ray autocorrelation function after Auger

We report results of a global autocorrelation analysis of the Auger data, with the aim to constrain the number density ns of ultrahigh energy cosmic ray (UHECR) sources, estimating at the same time the effect of the bias of UHECR sources and of the systematic energy scale uncertainty on ns. The data show no significant small-scale clustering which may be explained by magnetic deflections over scales of a few degrees. The case of continuous, uniformly distributed sources is disfavored at 99% C.L. and the fit improves if the sources follow the large-scale structure of matter in the universe. Active galactic nuclei fit well the deduced number density and luminosities.