INVESTIGADORES
MARIAZZI Analisa Gabriela
artículos
Título:
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter
Autor/es:
PIERRE AUGER COLLABORATION (J. ABRAHAM, ... , A. MARIAZZI,ET AL)
Revista:
ASTROPARTICLE PHYSICS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2010 vol. 34 p. 314 - 326
ISSN:
0927-6505
Resumen:
Data collected by the Pierre Auger Observatory through 31 August 2007
showed evidence for anisotropy in the arrival directions of cosmic rays
above the GreisenZatsepinKuzmin energy threshold, 6 × 1019 eV.
The anisotropy was measured by the fraction of arrival directions that
are less than 3.1° from the position of an active galactic nucleus
within 75 Mpc (using the Véron-Cetty and Véron 12th catalog). An updated
measurement of this fraction is reported here using the arrival
directions of cosmic rays recorded above the same energy threshold
through 31 December 2009. The number of arrival directions has increased
from 27 to 69, allowing a more precise measurement. The correlating
fraction is , compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of .
The enlarged set of arrival directions is examined also in relation to
other populations of nearby extragalactic objects: galaxies in the 2
Microns All Sky Survey and active galactic nuclei detected in hard
X-rays by the Swift Burst Alert Telescope. A celestial region around the
position of the radiogalaxy Cen A has the largest excess of arrival
directions relative to isotropic expectations. The 2-point
autocorrelation function is shown for the enlarged set of arrival
directions and compared to the isotropic expectation.