INVESTIGADORES
MOLLERACH Maria Silvia
artículos
Título:
Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
Autor/es:
THE PIERRE AUGER COLLABORATION, INCLUYE S. MOLLERACH
Revista:
ASTROPARTICLE PHYSICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2009 vol. 31 p. 399 - 406
ISSN:
0927-6505
Resumen:
From direct observations of the longitudinal development of ultra-high energy
air showers performed with the Pierre Auger Observatory, upper limits of 3.8%,
2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray
photons above 2, 3, 5 and 10 EeV (1 EeV = 10^18 eV) respectively. These are the
first experimental limits on ultra-high energy photons at energies below 10
EeV. The results complement previous constraints on top-down models from array
data and they reduce systematic uncertainties in the interpretation of shower
data in terms of primary flux, nuclear composition and proton-air
cross-section.