212 research outputs found

    The Pierre Auger Project and Enhancements

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    The current status of the scientific results of the Auger Observatory will be discussed which include spectrum, anisotropy in arrival directions, chemical composition analyses, and limits on neutrino and photon fluxes. A review of the Observatory detection systems will be presented. Auger has started the construction of its second phase which encompasses antennae for radio detection of cosmic rays, high-elevation telescopes, and surface plus muon detectors. Details will be presented on the latter, AMIGA (Auger Muons and Infill for the Ground Array), an Auger project consisting of 85 detector pairs each one composed of a surface water-Cherenkov detector and a buried muon counter. The detector pairs are arranged in an array with spacings of 433 and 750 m in order to perform a detailed study of the 10^17 eV to 10^19 eV spectrum region. Preliminary results on the performance of the 750 m array of surface detectors and the first muon counter prototype will be presented.Comment: 10 pages, 8 figures, VIII Latin American Symposium on Nuclear Physics and Applications December 15-19, 2009, Santiago, Chil

    Deployment and performance of a Low-Energy-Threshold Skipper-CCD inside a nuclear reactor

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    Charge Coupled Devices (CCD) are used for reactor neutrino experiments and already shown their potential in constraining new physics models. The prospect of a Skipper-CCD experiment looking for standard and beyond standard model physics (BSM) in a nuclear reactor has been recently evaluated for different benchmark scenarios. Here we report the installation of the first 2 g Skipper-CCD inside the containment building of a 2 GWth_{th} nuclear power plant, positioned 12 meters from the center of the reactor core. We discuss the challenges involved in the commissioning of the detector and present data acquired during reactor ON and reactor OFF periods, with the detector operating with a sub-electron readout noise of 0.17 e-. The ongoing efforts to improve sensitivities to CEvNS and BSM interaction are also discussed.Comment: 12 pages, 7 figures, 1 tabl

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa

    Reconstruction of inclined air showers detected with the Pierre Auger Observatory

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    We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60∘60^\circ detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of Cosmology and Astroparticle Physics (JCAP

    Highlights from the Pierre Auger Observatory

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    The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km2^2 str and provides us with an unprecedented quality data set. The performance and stability of the detectors and their enhancements are described. Data analyses have led to a number of major breakthroughs. Among these we discuss the energy spectrum and the searches for large-scale anisotropies. We present analyses of our Xmax_{max} data and show how it can be interpreted in terms of mass composition. We also describe some new analyses that extract mass sensitive parameters from the 100% duty cycle SD data. A coherent interpretation of all these recent results opens new directions. The consequences regarding the cosmic ray composition and the properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray Conference, Rio de Janeiro 201

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200
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