Search for first harmonic modulation in the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory
Abstract
We present the results of searches for dipolar-type anisotropies in different energy ranges above 2.5 × 1017 eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% C.L. for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.
- Publication:
-
Astroparticle Physics
- Pub Date:
- March 2011
- DOI:
- 10.1016/j.astropartphys.2010.12.007
- arXiv:
- arXiv:1103.2721
- Bibcode:
- 2011APh....34..627P
- Keywords:
-
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 28 pages, 11 figures