2,813 research outputs found
Measurement of Ultra-High Energy Cosmic Rays with CHICOS
No full textThe California HIgh school Cosmic ray ObServatory (CHICOS) is a ground-based scintillator array designed to measure the extended air showers of ultra-high energy cosmic rays. The goal of the project is to gain insight into the origin of ultra-high energy cosmic rays by measuring the energy spectrum and the distribution of arrival directions.
The CHICOS array has been in operation since 2003. It consists of 77 pairs of scintillator dectectors deployed at schools in the San Fernando and San Gabriel valleys near Los Angeles, and is designed to observe cosmic ray air showers at energies of 10^18 eV and above. In addition, the Chiquita subarray is designed to observe smaller showers in the energy range of 1016 - 1019 eV.
We present new descriptions of the air shower lateral distribution function and time distribution function, which have been derived from AIRES-generated simulated air showers. The new functions are specific to the CHICOS altitude and allow for a maximum likelihood shower reconstruction method, which is more appropriate to the CHICOS data than the χ2 minimization method. We present several analyses of the accuracy of the reconstruction software in the energy ranges available to the Chiquita and CHICOS arrays.
The energy spectrum between 1017 eV and 1019 eV has been measured by the Chiquita subarray. At the lowest energy range, it is found to agree with previous measurements, while the measured flux falls below previous experiments for energies greater than approximately 1017.5 eV. The CHICOS energy spectrum above 1018.4 eV is found to agree with previous results published by AGASA. However, we do not observe the cutoff in the spectrum at 1020 eV reported more recently by the Auger and HiRes Collaborations.
A correlation analysis between CHICOS data and nearby active galactic nuclei (AGN) was performed. No excess of cosmic rays was observed in the vicinity of nearby AGN. The maximum correlation was observed for cosmic ray events with E > 1020 eV and for AGN with z < 0.009, with Pchance = 21%. This is consistent with random correlations from an isotropic distribution, a result also found by HiRes, but in disagreement with Auger.</p
The Pierre Auger Observatory I: The Cosmic Ray Energy Spectrum and Related Measurements - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4809.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the cosmic ray energy spectrum at the highest energies with the Pierre Auger Observatory
The Pierre Auger Observatory I: The Cosmic Ray Energy Spectrum and Related Measurements - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4809.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the cosmic ray energy spectrum at the highest energies with the Pierre Auger Observatory
The Pierre Auger Observatory II: Studies of Cosmic Ray Composition and Hadronic Interaction models - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4804.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers
The Pierre Auger Observatory II: Studies of Cosmic Ray Composition and Hadronic Interaction models - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4804.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers
The Pierre Auger Observatory III: Other Astrophysical Observations - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4805.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger Observator
The Pierre Auger Observatory III: Other Astrophysical Observations - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4805.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger Observator
The Pierre Auger Observatory IV: Operation and Monitoring - Collection of papers in http://arxiv.org/ftp/arxiv/papers/1107/1107.4806.pdf
No full textContributions of the Auger Collaboration to the 32nd International Cosmic Ray Conference, Beijing, August, 2011: Technical reports on operations and monitoring of the Pierre Auger Observator
The Pierre Auger Cosmic Ray Observatory
No full textThe Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world׳s largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 10 eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000 km overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km, 61-detector infilled array with 750 m spacing. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory
The UHE cosmic ray energy spectrum measured by the Pierre Auger Observatory
No full textThe UHE cosmic ray spectrum has been measured with the Pierre Auger Observatory using two complementary techniques. Those techniques are described, emphasising the advantages and cross-checks afforded by the hybrid nature of the Observatory. © 2011 Elsevier B.V.Bruce R. Dawson, for the Pierre Auger Collaboratio
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