61. Large-Scale Distribution of Arrival Directions of Cosmic Rays Detected at the Pierre Auger Observatory and the Telescope Array above 10[sup]19 eVOlivier Deligny, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, objavljeni znanstveni prispevek na konferenci Opis: The large-scale distribution of arrival directions of
high-energy cosmic rays is a key observable in attempts to
understanding their origin. The dipole and quadrupole moments
are of special interest in revealing potential anisotropies.
An unambiguous measurement of these moments as well as
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 Pierre Auger Observatory and the Telescope Array above
10[sup]19 eV has been performed. Thanks to the full-sky
coverage, the measurement of the dipole moment reported in
this study does not rely on any assumption on the underlying
flux of cosmic rays. As well, the resolution on the quadrupole
and higher order moments is the best ever obtained. The
resulting multipolar expansion of the flux of cosmic rays
allows a series of anisotropy searches to be performed,
and in particular to report on the first angular power
spectrum of cosmic rays. This allows a comprehensive
description of the angular distribution of cosmic rays
above 10[sup]19 eV. Ključne besede: Pierre Auger Observatory, Telescope Array, high-energy cosmic rays, large-scale anisotropies, angular power spectrum Objavljeno v RUNG: 08.03.2016; Ogledov: 5087; Prenosov: 193 Celotno besedilo (462,61 KB) |
62. Combined fit of spectrum and composition data as measured by the Pierre Auger ObservatoryAndrea Di Matteo, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, objavljeni znanstveni prispevek na konferenci Opis: We present a combined fit of both flux and composition of
ultra-high energy cosmic rays as measured by the Pierre Auger
Observatory. The fit has been performed for energies above
5 × 10[sup]18 eV, i.e. the region of the all-particle spectrum
above the so-called “ankle” feature. A simple astrophysical model consisting of identical sources has been adopted, where
nuclei are injected with a rigidity dependent mechanism and the
sources are uniformly distributed in a comoving volume.
The fit results suggest a source model characterized by
relatively low maximum injection energies and hard spectral
indices. The impact of different sources of systematic
uncertainties in the above result is discussed. Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, energy spectrum, elemental composition, combined data fit Objavljeno v RUNG: 03.03.2016; Ogledov: 5212; Prenosov: 234 Celotno besedilo (704,98 KB) |
63. The flux of ultra-high energy cosmic rays after ten years of operation of the Pierre Auger ObservatoryInés Valiño, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, objavljeni znanstveni prispevek na konferenci Opis: The flux of ultra-high energy cosmic rays has been measured
with unprecedented precision at the Pierre Auger Observatory.
We report an update of the all-sky flux of cosmic rays above 3 x 10 [sup] 17 eV obtained by combining four
independent data sets. These measurements are based on data
from the surface detector arrays (divided into two sets according to the shower zenith angle), from a nested, denser,
detector array, and hybrid events measured simultaneously with
both the fluorescence detector and the surface detector array.
The spectral features are presented in detail and the
systematic uncertainties are addressed. The huge amount of data
collected to date, with a total exposure exceeding
50,000 km2 sr yr, together with the wide range of sky observed
(in declination from -90[deg] to 45[deg]) also allow us to
measure the energy spectrum from different regions of the sky.
We present the results of the search for a dependence of the
measured flux on the declination of the incoming directions. Ključne besede: ultra-high energy cosmic rays
energy spectrum
Pierre Auger Observatory Objavljeno v RUNG: 02.03.2016; Ogledov: 6305; Prenosov: 228 Celotno besedilo (755,08 KB) |
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