84 research outputs found

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    From Olfaction to Emotions: An Interactive and Immersive Experience

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    International audienceThe causal relationship between olfactory perception and human emotions has been widely studied and accepted by various fields including, but not limited to, health, marketing, and multimedia. In this work-in-progress paper, we present an olfactive, interactive and immersive experience taking place during the World Creativity & Innovation Week in Nantes, France, in April 2022. Through this experience, we aim to observe and exploit the existing relationship between smells and emotions by measuring, in real time, participants' physiological reactions (e.g., heart rate and skin conductance) to a given olfactive stimulus. Based on the obtained signals, appropriate multimedia content, implemented in collaboration with local partners, is interactively displayed in the room with a view to further immerse the participants in their experience

    Défi MOREST - Mortalités estivales de l'huître creuse Crassostrea gigas - Caractérisation des facteurs de risques associés au mortalites estivales - Synthèse du thème I - Évaluation des risques dans les écosystèmes conchylicoles. (La Rochelle 14- 15 mars 2006)

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    L'objectif de ce thème est de préciser les relations entre Mortalités et Environnement, en déclinant cette relation à travers les "risques environnementaux" caractérisés depuis le début du programme MOREST. La température, les bassins versant etlou l'eau douce, la ressource trophique, le compartiment sédimentaire, autant de facteurs impliqués directement ou indirectement dans les processus de mortalités de Crassostrea gigas. Ces facteurs d'influence "externe" sont étudiés à différentes échelles d'espace ("nationale", "régionale", "sites") et de temps (annuelle, mensuelle, bimensuelle, journalière, horaire, infra horaire) en s'appuyant sur des données issues de bases institutionnelles (REMORA', REPHY~, METEO-FRANCE) et sur les résultats de terrain obtenus depuis le début du programme MOREST sur les 3 sites ateliers (Marennes Oléron, Rivière d'Auray, Baie des Veys

    Estimation des flux de contaminants particulaires à Arles et Jons (2013)

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    En février 2013, le Conseil Scientifique de l’OSR a construit collectivement la structuration du 3ème programme scientifique. La structuration et le nombre d’axes de recherche ont évolué afin de s’adapter aux nouveaux besoins des opérationnels et offrir la possibilité de réunir les équipes scientifiques pour développer des démarches plus interdisciplinaires. Les quatre premiers axes structurent des champs thématiques spécifiques. Ils sont alimentés par un système d’observation et de mesures, et reposent sur un axe commun et transversal qui vient techniquement soutenir toutes les actions de recherche via le développement d’outils de modélisation, la gestion collective des données ou encore la valorisation des résultats (synthèse de l’ensemble des connaissances produites). L’OSR3 a été conçu comme une phase de transition dans le cadre de la relance du nouveau Plan Rhône. Cette programmation a permis à la fois de consolider les acquis des quatre premières années de recherche, d’assurer la continuité des mesures et de préparer les actions ensuite mises en place dans la programmation 2015/2017
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