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We study the arrival directions of 69 ultra-high energy cosmic rays (UHECRs)observed at the Pierre Auger Observatory (PAO) with energies exceeding 55 EeV.We investigate whether the UHECRs exhibit the anisotropy signal expected if theprimary particles are protons that originate in galaxies in the local universe,or in sources correlated with these galaxies. We cross-correlate the UHECRarrival directions with the positions of IRAS-PSCz and 2MASS-6dF galaxiestaking into account particle energy losses during propagation. This is thefirst time that the 6dF survey is used in a search for the sources of UHECRsand the first time that the PSCz survey is used with the full 69 PAO events.The observed cross-correlation signal is larger for the PAO UHECRs than for 94%(98%) of realisations from an isotropic distribution when cross-correlated withthe PSCz (6dF). On the other hand the observed cross-correlation signal islower than that expected from 85% of realisations, had the UHECRs originated ingalaxies in either survey. The observed cross-correlation signal does exceedthat expected by 50% of the realisations if the UHECRs are randomly deflectedby intervening magnetic fields by 5 degrees or more. We propose a new method ofanalysing the expected anisotropy signal, by dividing the predicted UHECRsource distribution into equal predicted flux radial shells, which can helplocalise and constrain the properties of UHECR sources. We find that the 69 PAOevents are consistent with isotropy in the nearest of three shells we define,whereas there is weak evidence for correlation with the predicted sourcedistribution in the two more distant shells in which the galaxy distribution isless anisotropic.

A Search for Correlation of Ultra-High Energy Cosmic Rays with IRAS-PSCz and 2MASS-6dF Galaxies