1,721,271 research outputs found
Aerosol attenuation measurements for cosmic rays experiments: the Pierre Auger Observatory experience and the ARCADE project
No full textMeasurement of the muon production depths at the Pierre Auger Observatory
No full textThe muon content of extensive air showers is an observable sensitive to the primary composition and to the hadronic interaction properties. The Pierre Auger Observatory uses water-Cherenkov detectors to measure particle densities at the ground and therefore is sensitive to the muon content of air showers. We present here a method which allows us to estimate the muon production depths by exploiting the measurement of the muon arrival times at the ground recorded with the Surface Detector of the Pierre Auger Observatory. The analysis is performed in a large range of zenith angles, thanks to the capability of estimating and subtracting the electromagnetic component, and for energies between 10(19.2) and 10(20)eV
Atmospheric aerosol characterization using the central laser facility at the Pierre Auger Observatory
No full textThe Fluorescence Detector of the Pierre Auger Observatory uses the atmosphere as a huge calorimeter that needs continuous
monitoring to ensure unbiased physics results. The Central Laser Facility (CLF), a calibrated laser source located near the centre
of the Observatory, is used to measure the light attenuation due to aerosols, highly variable even on time scales of one hour. Two
independent, fully compatible procedures based on the analysis of CLF vertical events have been developed. Five years of hourly
aerosol characterization are provide
Elves, Forbush Decreases and Solar Activity Studies at the Pierre Auger Observatory
No full textThe Pierre Auger Observatory, designed to observe cosmic rays at the highest energies, can also be
a valid ground based instrument for the observation of transient luminous events and for studying
the modulation of galactic cosmic rays due to solar activity. The Fluorescence Detector can observe
elves, transient luminous emissions from altitudes between 80 km and 95 km above sea level, with
timescales of tens of microseconds, which are triggered by lightning activity. A dedicated trigger
and an extended readout scheme were introduced to enhance detection efficiency of these events and
to improve the knowledge of some peculiar characteristics. The low energy mode of the Surface
Detector, on the other hand, records variations in the flux of low energy secondary particles with
extreme detail.With the Scaler mode, it is possible to register the rate of signals for deposited energies
between 15 MeV - 100 MeV; the Histogram mode, using the calibration peak and charge histograms
of the individual pulses detected by each water-Cherenkov station, covers different deposited energy
ranges up to 1 GeV. The variations in the flux of galactic cosmic rays have been studied on short
and intermediate time scales (Forbush decreases), but also a long-term analysis, which shows the
sensitivity of the Observatory to the solar cycle variation, is in progress
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory
No full textWe present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60°, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ~ 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for
Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory
No full textThe Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an EÀ2 differential energy spectrum the limit on the single-flavor neutrino is E2 dN=dE < 1.74 x 10^7 GeVcmÀ2 sÀ1 srÀ1 at 90% C.L. in the energy range 1 x10^17 eV < E < 1 x10^20 eV
The Rapid Atmospheric Monitoring System of the Pierre Auger Observatory
No full textThe Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 1017 eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e. g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest, and indicate that the air fluorescence measurements affected by clouds and aerosols are effectively corrected using measurements from the regular atmospheric monitoring program. We find that the rapid monitoring program has potential for supporting dedicated physics analyses beyond the standard event reconstruction
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