Searches for Anisotropies in the Arrival Directions of the Highest Energy Cosmic Rays Detected by the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION (A. AAB, ..., A.D. SUPANITSKY, ...)

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2015 vol. 804 p. 1 - 18

0004-637X

We analyze the distribution of arrival directions of ultra-high-energy cosmic rays recorded at the Pierre Auger Observatory in 10 years of operation. The data set, about three times larger than that used in earlier studies, includes arrival directions with zenith angles up to 80°, thus covering from -90deg to +45deg in declination. After updating the fraction of events correlating with the active galactic nuclei (AGNs) in the Véron-Cetty and Véron catalog, we subject the arrival directions of the data with energies in excess of 40 EeV to different tests foranisotropy. We search for localized excess fluxes, self-clustering of event directions at angular scales up to 30deg, and different threshold energies between 40 and 80 EeV. We then look for correlations of cosmic rays with celestial structures both in the Galaxy (the Galactic Center and Galactic Plane) and in the local universe (the SuperGalacticPlane). We also examine their correlation with different populations of nearby extragalactic objects: galaxies in the 2MRS catalog, AGNs detected by Swift-BAT, radio galaxies with jets, and the Centaurus A (Cen A) galaxy. None of the tests show statistically significant evidence of anisotropy. The strongest departures from isotropy (post-trial probability ~1.4%) are obtained for cosmic rays with E > 58 EeV in rather large windows around Swift AGNs closer than 130 Mpc and brighter than 1044 erg s^−1 (18deg radius), and around the direction ofCen A (15deg radius).