Measurement of the first harmonic modulation in the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory: towards the detection of dipolar anisotropies over a wide energy range

THE PIERRE AUGER COLLABORATION (AUTOR 434 DE 474); M. TUEROS

Rio de Janeiro

Conferencia; 33rd International Cosmic Ray Conference (ICRC 2013); 2013

International Union of Pure and Applied Physics (IUPAP)

First harmonic analyses of the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory are reported. We here update the upper limits on the dipole component in the equatorial plane andextend the previous results to lower energies by using data recorded by the infill surface detector array. On the other hand, a possible consistency in ordered energy intervals of the phase was observed and reported, consistency that may be indicative of anisotropies whose amplitudes are too small to stand out above the background noiseinduced by the finite statistics accumulated so far. Based on this posterior observation, a prescribed single shot test was designed on June 25 2011 to establish at 99% CL whether this consistency is real or not. Since the effect has been observed over a wide energy range, the test makes use of data of both the infill and the regular surfacedetector arrays. At about mid-term, the status of this prescription is reported.