111. 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, published scientific conference contribution Abstract: 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. Keywords: Pierre Auger Observatory, Telescope Array, high-energy cosmic rays, large-scale anisotropies, angular power spectrum Published in RUNG: 08.03.2016; Views: 4517; Downloads: 189 Full text (462,61 KB) |
112. Report of the Working Group on the Composition of Ultra-High Energy Cosmic RaysMichael Unger, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The atmospheric depth, Xmax, at which the particle number of
an air shower reaches its maximum is a good indicator for the
mass of the primary particle. We present a comparison of the
energy evolution of the mean of Xmax as measured by the
Telescope Array and c Collaborations. After
accounting for the different resolutions, acceptances and
analysis strategies of the two experiments, the two results are
found to be in good agreement within systematic uncertainties. Keywords: Pierre Auger Observatory, Telescope Array, Ultra-High Energy Cosmic Rays, elemental composition, extensive air showers, the atmospheric depth of the air shower maximum Published in RUNG: 08.03.2016; Views: 4698; Downloads: 235 Full text (329,86 KB) |
113. Search for a correlation between the UHECRs measured by the Pierre Auger Observatory and the Telescope Array and the neutrino candidate events from IceCubeAsen Christov, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: We have conducted three searches for correlations between
ultra-high energy cosmic rays detected by the Telescope Array
and the Pierre Auger Observatory, and high-energy neutrino
candidate events from IceCube. Two cross-correlation analyses
with UHECRs are done: one with 39 cascades from the IceCube
‘high-energy starting events’ sample and the other with 16
high-energy ‘track events’. The angular separation between the
arrival directions of neutrinos and UHECRs is scanned over.
The same events are also used in a separate search using a
maximum likelihood approach, after the neutrino arrival
directions are stacked. To estimate the significance we assume
UHECR magnetic deflections to be inversely proportional to
their energy, with values 3◦, 6◦ and 9◦ at 100 EeV to allow for
the uncertainties on the magnetic field strength and UHECR
charge. A similar analysis is performed on stacked UHECR
arrival directions and the IceCube sample of through-going
muon track events which were optimized for neutrino point-
source searches. Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, Telescope Array, high-energy neutrinos, IceCube, correlation search Published in RUNG: 08.03.2016; Views: 4957; Downloads: 192 Full text (1,11 MB) |
114. Education, Outreach and Public Relations of the Pierre Auger ObservatoryCharles Timmermans, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The scale and scope of the physics studied at the Pierre Auger
Observatory continue to offer significant opportunities for
original outreach work. Education, outreach and public
relations of the Auger Collaboration are coordinated in a
dedicated task whose goals are to encourage and support
a wide range of efforts that link schools and the public with
the Auger scientists and the science of cosmic rays, particle
physics, and associated technologies. We focus on the impact of
the Collaboration in Mendoza Province, Argentina and beyond.
The Auger Visitor Center in Malargüe has hosted over 95,000
visitors since 2001, and a fifth Collaboration-sponsored
science fair was held on the Observatory campus in November
2014. The Rural Schools Program, which is run by Observatory
staff and which brings cosmic-ray science and infrastructure
improvements to remote schools, continues to broaden its
reach. Numerous online resources, video documentaries, and
animations of extensive air showers have been created for wide
public release. Increasingly, collaborators draw on these
resources to develop Auger related displays and outreach events
at their institutions and in public settings to disseminate the
science and successes of the Observatory worldwide. We also
highlight education and outreach activities associated with the
planned upgrade of the Observatory’s detector systems and
future physics goals. Keywords: Pierre Auger Observatory, cosmic rays physics, education, outreach, public relations Published in RUNG: 03.03.2016; Views: 4611; Downloads: 184 Full text (4,12 MB) |
115. AugerNext: R&D studies at the Pierre Auger Observatory for a next generation ground-based ultra-high energy cosmic-ray experimentAndreas Haungs, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The findings so far of the Pierre Auger Observatory and those
of the Telescope Array define some requirements for a possible
next generation global cosmic ray observatory: it needs to be
considerably increased in size, it needs enhanced sensitivity
to composition, and it has to cover the full sky. At the Pierre
Auger Observatory, AugerNext aims to conduct some innovative
initial research studies on a design of a sophisticated hybrid
detector fulfilling these demands. Within a European supported
ASPERA/APPEC (Astroparticle Physics European Consortium)
project for the years 2011-2014, such R&D studies primarily
focused on the following areas: i) consolidation of the
detection of cosmic rays using MHz radio antennas; ii) proof-
of-principle of cosmic ray microwave detection; iii) test of
the large-scale application of new generation photo sensors;
iv) generalization of data communication techniques; and v)
development of new schemes for muon detection with surface
arrays. The AugerNext Consortium consists of 14 principal
investigators from 9 countries. This contribution summarizes
some achievements of the R&D studies within the AugerNext
project. Keywords: ultra-high energy cosmic-ray experiments, Pierre Auger Observatory, Telescope Array, AugerNext research and development study Published in RUNG: 03.03.2016; Views: 5020; Downloads: 198 Full text (594,23 KB) |
116. Status and Prospects of the Auger Engineering Radio ArrayJohannes Schulz, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The Auger Engineering Radio Array (AERA) is an extension of the
Pierre Auger Observatory. It is used to detect radio emission
from extensive air showers in the 30 - 80 MHz frequency band.
A focus of interest is the dependence of the radio emission on
shower parameters such as the energy and the atmospheric depth
of the shower maximum. After three phases of deployment, AERA
now consists of 153 autonomous radio stations with different
spacings, covering an area of about 17 km2. The size, station
spacings, and geographic location at the same site or near other
Auger extensions, are all targeted at cosmic ray energies above
10[sup]17 eV. The array allows us to explore different
technical schemes to measure the radio emission as well as to
cross calibrate our measurements with the established baseline
detectors of the Auger Observatory. We present the most recent
technological developments and selected experimental results
obtained with AERA. Keywords: Pierre Auger Observatory, the Auger Engineering Radio Array (AERA), radio emission from extensive air showers, detector cross-calibration Published in RUNG: 03.03.2016; Views: 4639; Downloads: 196 Full text (2,79 MB) |
117. Automated procedures for the Fluorescence Detector calibration at the Pierre Auger ObservatoryGaetano Salina, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The quality of the physics results, derived from the analysis
of the data collected at the Pierre Auger Observatory depends
heavily on the calibration and monitoring of the components of
the detectors. It is crucial to maintain a database containing complete information on the absolute calibration of all
photomultipliers and their time evolution. The low rate of the
physics events implies that the analysis will have to be made
over a long period of operation. This requirement imposes a
very organized and reliable data storage and data management
strategy, in order to guarantee correct data preservation and
high data quality. The Fluorescence Detector (FD) consists of
27 telescopes with about 12,000 phototubes which have to be
calibrated periodically. A special absolute calibration system
is used. It is based on a calibrated light source with a
diffusive screen, uniformly illuminating photomultipliers
of the camera. This absolute calibration is performed every few
years, as its use is not compatible with the operation of the
detector. To monitor the stability and the time behavior,
another light source system operates every night of data
taking. This relative calibration procedure yields more than
2×10[sup]4 raw files each year, about 1 TByte/year. In this
paper we describe a new web-interfaced database architecture
to manage, store, produce and analyse FD calibration data.
It contains the configuration and operating parameters of the
detectors at each instant and other relevant functional
parameters that are needed for the analysis or to monitor
possible instabilities, used for the early discovery of
malfunctioning components. Based on over 10 years of
operation, we present results on the long term performance
of FD and its dependence on environmental variables. We also
report on a check of the absolute calibration values by
analysing the signals left by stars traversing the FD field of
view. Keywords: Pierre Auger Observatory, Fluorescence Detector, detector calibration and monitoring, automated calibration procedure Published in RUNG: 03.03.2016; Views: 4374; Downloads: 202 Full text (1,06 MB) |
118. Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscopePedro Assis, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The Pierre Auger Observatory operates a hybrid detector
composed of a Fluorescence Detector and a Surface Detector
array. Water-Cherenkov detectors (WCD) are the building blocks
of the array and as such play a key role in the detection of
secondary particles at the ground. A good knowledge of the
detector response is of paramount importance to lower
systematic uncertainties and thus to increase the capability
of the experiment in determining the muon content of the
extensive air showers with a higher precision.
In this work we report on a detailed study of the detector
response to single muons as a function of their trajectories
in the WCD. A dedicated Resistive Plate Chambers (RPC)
hodoscope was built and installed around one of the detectors.
The hodoscope is formed by two stand-alone low gas flux
segmented RPC detectors with the test water-Cherenkov detector
placed in between. The segmentation of the RPC detectors is of
the order of 10 cm. The hodoscope is used to trigger and
select single muon events in different geometries. The signal
recorded in the water-Cherenkov detector and performance
estimators were studied as a function of the trajectories of
the muons and compared with a dedicated simulation.
An agreement at the percent level was found, showing that the
simulation correctly describes the tank response. Keywords: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope Published in RUNG: 03.03.2016; Views: 4767; Downloads: 198 Full text (1,27 MB) |
119. The Energy Content of Extensive Air Showers in the Radio Frequency Range of 30-80 MHzChristian Glaser, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: At the Auger Engineering Radio Array (AERA) of the Pierre Auger
Observatory, we have developed a new method to measure the
total amount of energy that is transferred from the primary
cosmic ray into radio emission. We find that this radiation
energy is an estimator of the cosmic ray energy. It scales
quadratically with the cosmic ray energy, as expected for
coherent emission. We measure 15.8 MeV of radiation energy for
a 1 EeV air shower arriving perpendicular to the geomagnetic
field at the Auger site, in the frequency band of the detector
from 30 to 80 MHz. These observations are compared to the data
of the surface detector of the Observatory, which provide
well-calibrated energies and arrival directions of the cosmic
rays. We find energy resolutions of the radio reconstruction
of 22% for the complete data set, and 17% for a high-quality
subset containing only events with at least five stations with
signal. Keywords: Pierre Auger Observatory, the Auger Engineering Radio Array (AERA), extensive air showers, radio reconstruction: energy resolution Published in RUNG: 03.03.2016; Views: 4763; Downloads: 210 Full text (574,66 KB) |
120. The AMIGA Muon Counters of the Pierre Auger Observatory: Performance and Studies of the Lateral Distribution FunctionBrian Wundheiler, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The AMIGA enhancement (Auger Muons and Infill for the Ground
Array) of the Pierre Auger Observatory consists of a 23.5 km2
infill area where air shower particles are sampled by water-
Cherenkov detectors at the surface and by 30 m2 scintillation
counters buried 2.3 m underground. The Engineering Array of
AMIGA, completed since February 2015, includes 37 scintillator
modules (290 m2) in a hexagonal layout. In this work, the muon
counting performance of the scintillation detectors is analysed
over the first 20 months of operation. Parametrisations of the
detector counting resolution and the lateral trigger
probability are presented. Finally, preliminary results on the observed muon lateral distribution function (LDF) are discussed. Keywords: Pierre Auger Observatory, AMIGA (Auger Muons and Infill for the Ground Array) muon
counters, muon lateral distribution function (LDF) Published in RUNG: 03.03.2016; Views: 4208; Downloads: 178 Full text (499,33 KB) |