We explore the possibility of a local origin for ultra high energy cosmic rays ( UHECRs ) .
Using the catalogue of Karachentsev et al .
including nearby galaxies with distances less than 10Mpc ( Local Volume ) , we search for a correlation with the sample of UHECR events released so far by the Pierre Auger collaboration .
The counterpart sample selection is performed with variable distance and luminosity cuts which extract the most likely sources in the catalogue .
The probability of chance correlation after penalizing for scans is 0.96 % , which corresponds to a correlation signal of 2.6 \sigma .
We find that the parameters that maximize the signal are \psi = 3.0 ^ { \circ } , D _ { \mathrm { max } } = 4 Mpc and M _ { \mathrm { B } } = -15 for the maximum angular separation between cosmic rays and galaxy sources , maximum distance to the source , and sources brighter than B -band absolute magnitude respectively .
This implies a preference for the UHECRs arrival directions to be correlated with the nearest and most luminous galaxies in the Local Volume , while the angular distance between the cosmic ray events and their possible sources is similar to that found by The Pierre Auger Collaboration using active galactic nuclei ( AGNs ) within 70-100Mpc instead of local galaxies .
We note that nearby galaxies with D < 10 Mpc show a similar correlation with UHECRs as compared to well-known particle accelerators such as AGNs , although less than 20 % of cosmic ray events are correlated to a source in our study .
However , the observational evidence for mixed composition in the high-energy end of the cosmic ray spectrum supports the possibility of a local origin for UHECRs , as CNO nuclei can travel only few Mpc without strong attenuation by the GZK effect , whereas the observed suppression in the energy spectrum would require more distant sources in the case of pure proton composition interacting with the CMB .