INVESTIGADORES
MARIAZZI Analisa Gabriela
artículos
Título:
Search for first harmonic modulation in the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory
Autor/es:
PIERRE AUGER COLLABORATION (J. ABRAHAM, ... , A. MARIAZZI,ET AL)
Revista:
ASTROPARTICLE PHYSICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2011 vol. 34 p. 627 - 639
ISSN:
0927-6505
Resumen:
Data collected by the Pierre Auger Observatory provide evidence for
anisotropy in the arrival directions of the cosmic rays with the
highest-energies, which are correlated with the positions of relatively
nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science
318 (2007) 938]. The correlation has maximum significance for cosmic
rays with energy greater than 6 × 1019 eV and AGN at a distance less than 75 Mpc.
We have confirmed the anisotropy at a confidence level of more than 99%
through a test with parameters specified a priori, using an independent
data set. The observed correlation is compatible with the hypothesis
that cosmic rays with the highest-energies originate from extra-galactic
sources close enough so that their flux is not significantly attenuated
by interaction with the cosmic background radiation (the
GreisenZatsepinKuzmin effect). The angular scale of the correlation
observed is a few degrees, which suggests a predominantly light
composition unless the magnetic fields are very weak outside the thin
disk of our galaxy. Our present data do not identify AGN as the sources
of cosmic rays unambiguously, and other candidate sources which are
distributed as nearby AGN are not ruled out. We discuss the prospect of
unequivocal identification of individual sources of the highest-energy
cosmic rays within a few years of continued operation of the Pierre
Auger Observatory.