# Searches for Large-Scale Anisotropy in the Arrival Directions of Cosmic Rays Detected above Energy of $10^{19}$ eV at the Pierre Auger Observatory and the Telescope Array

Abstract : Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above $10^{19}$ eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above $10^{19}$ eV. No significant deviation from isotropic expectations is found throughout the analyses performed. Upper limits on the amplitudes of the dipole and quadrupole moments are derived as a function of the direction in the sky, varying between 7% and 13% for the dipole and between 7% and 10% for a symmetric quadrupole.
Document type :
Journal articles
Domain :

http://hal.in2p3.fr/in2p3-01063005
Contributor : Dominique Girod <>
Submitted on : Thursday, September 11, 2014 - 10:50:15 AM
Last modification on : Thursday, November 19, 2020 - 12:59:03 PM

### Citation

A. Aab, J. Aublin, P. Billoir, M. Blanco, L. Caccianiga, et al.. Searches for Large-Scale Anisotropy in the Arrival Directions of Cosmic Rays Detected above Energy of $10^{19}$ eV at the Pierre Auger Observatory and the Telescope Array. The Astrophysical Journal, American Astronomical Society, 2014, 794, pp.172. ⟨10.1088/0004-637X/794/2/172⟩. ⟨in2p3-01063005⟩

Record views