literature

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

Collaboration
Jun, 2011
15 pages
Published in:
  • JCAP 06 (2011) 022
e-Print:
Report number:
  • FERMILAB-PUB-11-281-AD-AE-CD-TD
Experiments:

Citations per year

20112014201720202023051015
Abstract: (arXiv)
The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E>Eth=5.5×1019E>E_{th}=5.5\times 10^{19} eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E>EthE>E_{th} are heavy nuclei with charge ZZ, the proton component of the sources should lead to excesses in the same regions at energies E/ZE/Z. We here report the lack of anisotropies in these directions at energies above Eth/ZE_{th}/Z (for illustrative values of Z=6, 13, 26Z=6,\ 13,\ 26). If the anisotropies above EthE_{th} are due to nuclei with charge ZZ, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.
  • cosmic radiation: UHE
  • nucleus: heavy
  • cosmic radiation: particle identification
  • p: cosmic radiation
  • angular distribution
  • Auger
  • correlation
  • cosmic radiation: energy
  • cosmic radiation: acceleration
  • cosmic radiation: hadronic component