Examinando por Autor "The Pierre Auger collaboration"
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Ítem Acceso Abierto A catalog of the highest-energy cosmic rays recorded during phase I of operation of the Pierre Auger Observatory(American Astronomical Society, 2023-02-01) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationÍtem Acceso Abierto A search for photons with energies above 2×1017 eV using hybrid data from the low energy extensions of the Pierre Auger Observatory(Institute of Physics, 2022-07-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationÍtem Acceso Abierto Arrival directions of vosmic rays above 32 EeV from phase one of the Pierre Auger Observatory(Institute of Physics, 2022-08-20) Micheletti, M. I.; Binet, V.; The Pierre Auger collaborationÍtem Acceso Abierto Calibration of the underground muon detector of the Pierre Auger Observatory(IOP Publishing, 2021-04-06) The Pierre Auger collaboration; Freire, M. M.; Micheletti, M. I.Ítem Acceso Abierto Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory(Institute of Physics, 2024-01-01) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationThe combined fit of the measured energy spectrum and shower maximum depth distributions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models with homogeneous source distributions. Studies of the distribution of the cosmic-ray arrival directions show a better agreement with models in which a fraction of the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with catalogs such as that of starburst galaxies. Here, we present a novel combination of both analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data measured at the Pierre Auger Observatory. The model takes into account a rigidity-dependent magnetic field blurring and an energy-dependent evolution of the catalog contribution shaped by interactions during propagation. We find that a model containing a flux contribution from the starburst galaxy catalog of around 20% at 40 EeV with a magnetic field blurring of around 20◦ for a rigidity of 10 EV provides a fair simultaneous description of all three observables. The starburst galaxy model is favored with a significance of 4.5σ (considering experimental systematic effects) compared to a reference model with only homogeneously distributed background sources. By investigating a scenario with Centaurus A as a single source in combination with the homogeneous background, we confirm that this region of the sky provides the dominant contribution to the observed anisotropy signal. Models containing a catalog of jetted active galactic nuclei whose flux scales with the γ-ray emission are, however, disfavored as they cannot adequately describe the measured arrival directions.Ítem Acceso Abierto Constraints on metastable superheavy dark matter coupled to sterile neutrinos with the Pierre Auger Observatory(American Physical Society, 2024-04-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationDark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm ≲ 1.5 × 10−6ðMX=109 GeVÞ−2 for a mass MX of the dark-matter particle between 108 GeV and 1011 GeV.Ítem Acceso Abierto Deep-learning based reconstruction of the shower maximum Xmax using the water-Cherenkov detectors of the Pierre Auger Observatory(IOP Publishing, 2021-07-14) Freir, M. M.; Micheletti, M. I.; The Pierre Auger collaborationÍtem Acceso Abierto Design and implementation of the AMIGA embedded system for data acquisition(IOP Publishing, 2021-07-19) Binet, V.; The Pierre Auger collaborationÍtem Acceso Abierto Extraction of the muon signals recorded with the surface detector of the Pierre Auger Observatory using recurrent neural networks(IOP Publishing, 2021-07-12) Freire, M. M.; The Pierre Auger collaborationÍtem Acceso Abierto Impact of the magnetic horizon on the interpretation of the Pierre Auger Observatory spectrum and composition data(IOP Publishing, 2024-07-30) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationThe flux of ultra-high energy cosmic rays reaching Earth above the ankle energy (5 EeV) can be described as a mixture of nuclei injected by extragalactic sources with very hard spectra and a low rigidity cutoff. Extragalactic magnetic fields existing between the Earth and the closest sources can affect the observed CR spectrum by reducing the flux of low-rigidity particles reaching Earth. We perform a combined fit of the spectrum and distributions of depth of shower maximum measured with the Pierre Auger Observatory including the effect of this magnetic horizon in the propagation of UHECRs in the intergalactic space. We find that, within a specific range of the various experimental and phenomenological systematics, the magnetic horizon effect can be relevant for turbulent magnetic field strengths in the local neighbourhood in which the closest sources lie of order Brms ≃ (50–100) nG (20 Mpc/ds)(100 kpc/Lcoh) 1/2, with ds the typical intersource separation and Lcoh the magnetic field coherence length. When this is the case, the inferred slope of the source spectrum becomes softer and can be closer to the expectations of diffusive shock acceleration, i.e., ∝ E−2. An additional cosmic-ray population with higher source density and softer spectra, presumably also extragalactic and dominating the cosmic-ray flux at EeV energies, is also required to reproduce the overall spectrum and composition results for all energies down to 0.6 EeV.Ítem Acceso Abierto Measurement of the fluctuations in the number of muons in extensive Air showers with the Pierre Auger Observatory(American Physical Society, 2021-04-16) Freire, M. M.; The Pierre Auger collaborationÍtem Acceso Abierto Radio measurements of the depth of air-shower maximum at the Pierre Auger Observatory(American Physical Society, 2023-01-08) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationThe Auger Engineering Radio Array (AERA), part of the Pierre Auger Observatory, is currently the largest array of radio antenna stations deployed for the detection of cosmic rays, spanning an area of 17 km2 with 153 radio stations. It detects the radio emission of extensive air showers produced by cosmic rays in the 30-80 MHz band. Here, we report the AERA measurements of the depth of the shower maximum (Xmax), a probe for mass composition, at cosmic-ray energies between 1017.5 and 1018.8 eV, which show agreement with earlier measurements with the fluorescence technique at the Pierre Auger Observatory. We show advancements in the method for radio Xmax reconstruction by comparison to dedicated sets of corsika/coreas air-shower simulations, including steps of reconstruction-bias identification and correction, which is of particular importance for irregular or sparse radio arrays. Using the largest set of radio air-shower measurements to date, we show the radio Xmax resolution as a function of energy, reaching a resolution better than 15 g cm-2 at the highest energies, demonstrating that radio Xmax measurements are competitive with the established high-precision fluorescence technique. In addition, we developed a procedure for performing an extensive data-driven study of systematic uncertainties, including the effects of acceptance bias, reconstruction bias, and the investigation of possible residual biases. These results have been cross-checked with air showers measured independently with both the radio and fluorescence techniques, a setup unique to the Pierre Auger Observatory.Ítem Acceso Abierto Search for photons above 1018 eV by simultaneously measuring the atmospheric depth and the muon content of air showers at the Pierre Auger Observatory(American Physical Society, 2024-09-25) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationThe Pierre Auger Observatory is the most sensitive instrument to detect photons with energies above 1017 eV. It measures extensive air showers generated by ultrahigh energy cosmic rays using a hybrid technique that exploits the combination of a fluorescence detector with a ground array of particle detectors. The signatures of a photon-induced air shower are a larger atmospheric depth of the shower maximum (𝑋max) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced cascades. In this work, a new analysis technique in the energy interval between 1 and 30 EeV (1 EeV=1018 eV) has been developed by combining the fluorescence detector-based measurement of 𝑋max with the specific features of the surface detector signal through a parameter related to the air shower muon content, derived from the universality of the air shower development. No evidence of a statistically significant signal due to photon primaries was found using data collected in about 12 years of operation. Thus, upper bounds to the integral photon flux have been set using a detailed calculation of the detector exposure, in combination with a data-driven background estimation. The derived 95% confidence level upper limits are 0.0403, 0.01113, 0.0035, 0.0023, and 0.0021 km−2 sr−1 yr−1 above 1, 2, 3, 5, and 10 EeV, respectively, leading to the most stringent upper limits on the photon flux in the EeV range. Compared with past results, the upper limits were improved by about 40% for the lowest energy threshold and by a factor 3 above 3 EeV, where no candidates were found and the expected background is negligible. The presented limits can be used to probe the assumptions on chemical composition of ultrahigh energy cosmic rays and allow for the constraint of the mass and lifetime phase space of super-heavy dark matter particles.Ítem Acceso Abierto Search for spatial correlations of Neutrinos with Ultra-high-energy Cosmic Rays(Institute of Physics, 2022-08-03) The ANTARES collaboration; The IceCube collaboration; The Pierre Auger collaboration; The Telescope Array collaboration; Binet, V.; Micheletti, M. I.Ítem Acceso Abierto Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory(IOP Publishing, 2022-01-17) Binet, V.; Micheletti, M. I.; The Pierre Auger collaborationÍtem Acceso Abierto The energy spectrum of cosmic rays beyond the turn-down around 1017 eV as measured with the surface detector of the Pierre Auger Observatory(Springer Science and Business, 2021-11-02) Binet, V.; Micheletti, M. I.; The Pierre Auger collaboration