810 research outputs found

    Joint searches between gravitational-wave interferometers and high-energy neutrino telescopes: science reach and analysis strategies

    Get PDF
    Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters of gravitational waves (GWs) and high-energy neutrinos (HENs). A network of GW detectors such as LIGO and Virgo can determine the direction/time of GW bursts while the IceCube and ANTARES neutrino telescopes can also provide accurate directional information for HEN events. Requiring the consistency between both, totally independent, detection channels shall enable new searches for cosmic events arriving from potential common sources, of which many extra-galactic objects.Comment: 4 pages. To appear in the Proceedings of the 2d Heidelberg Workshop: "High-Energy Gamma-rays and Neutrinos from Extra-Galactic Sources", Heidelberg (Germany), January 13-16, 200

    Caracterización de la fenología de la vegetación a escala global mediante series temporales SPOT VEGETATION

    Full text link
    Revista oficial de la Asociación Española de Teledetección[EN] Land surface phenology from time series of satellite data are expected to contribute to improve the represen-tation of vegetation phenology in earth system models. We characterized the baseline phenology of the vegetation at the global scale from GEOCLIM-LAI, a global climatology of leaf area index (LAI) derived from 1-km SPOT VEGETATION time series for 1999-2010. The calibration with ground measurements showed that the start and end of season were best identified using respectively 30% and 40% threshold of LAI amplitude values. The satellite-derived phenology was spatially consistent with the global distributions of climatic drivers and biome land cover. The accuracy of the derived phenological metrics, evaluated using available ground observations for birch forests in Europe, cherry in Asia and lilac shrubs in North America showed an overall root mean square error lower than 19 days for the start, end and length of season, and good agreement between the latitudinal gradients of VEGETATION LAI phenology and ground data[ES] La teledetección debe contribuir a mejorar la representación de la fenología en los modelos climáticos. En este estudio se ha caracterizado la fenología típica de la vegetación a escala global mediante GEOCLIM-LAI, una climatología del índice de área foliar (LAI) calculada a partir de series temporales en el periodo 1999-2010 de datos SPOT VEGETATION a 1-km de resolución espacial. A partir de la calibración con observaciones in situ, el inicio y fin de la estación de crecimiento se han definido como la fecha para la cual el LAI alcanza, respectivamente, el 30% y 40% de la amplitud de su ciclo anual. Los patrones espaciales de la fenología de satélite muestran una gran consistencia con la distribución espacial de cubiertas vegetales y factores climáticos. La comparación con medidas in situ para las fe-nofases correspondientes al inicio, fin y duración de la estación de crecimiento de abedul común en Europa, cerezo en Asia y lilo en Norte América muestra errores medios menores de 19 días, y un gran acuerdo en el gradiente latitudinal de la fenología observada in situ y estimada a partir de series temporales LAI VEGETATION.Este trabajo ha sido financiado en parte por el programa Europeo de observación Copernicus Global Land, y los proyectos FP7 geoland2 (218795), GIOBIO (32-566), LONGLOVE (32-594), CGL2013-48074-P, SGR 2014-274 y IMBALANCE-P (ERC-2013-SyG-610028). A. Verger fue beneficiario de un contrato Juan de la Cierva del Ministerio de Ciencia e Innovación, Gobierno de España.Verger, A.; Filella, I.; Baret, F.; Peñuelas, J. (2016). Land surface phenology from SPOT VEGETATION time series. Revista de Teledetección. (47):1-11. https://doi.org/10.4995/raet.2016.5718SWORD1114

    The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

    Full text link
    A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200

    The AMS-RICH velocity and charge reconstruction

    Full text link
    The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.Comment: Contribution to the ICRC07, Merida, Mexico (2007); Presenter: F. Bara

    The RICH detector of the AMS-02 experiment: status and physics prospects

    Full text link
    The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV. It is equipped with several subsystems, one of which is a proximity focusing RICH detector with a dual radiator (aerogel+NaF) that provides reliable measurements for particle velocity and charge. The assembly and testing of the AMS RICH is currently being finished and the full AMS detector is expected to be ready by the end of 2008. The RICH detector of AMS-02 is presented. Physics prospects are briefly discussed.Comment: 5 pages. Contribution to the 10th ICATPP Conference on Astroparticle, Particle, Space Physics, Detectors and Medical Physics Applications (Como 2007). Presenter: Rui Pereir

    Global Wheat Head Detection (GWHD) dataset: a large and diverse dataset of high resolution RGB labelled images to develop and benchmark wheat head detection methods

    Get PDF
    Detection of wheat heads is an important task allowing to estimate pertinent traits including head population density and head characteristics such as sanitary state, size, maturity stage and the presence of awns. Several studies developed methods for wheat head detection from high-resolution RGB imagery. They are based on computer vision and machine learning and are generally calibrated and validated on limited datasets. However, variability in observational conditions, genotypic differences, development stages, head orientation represents a challenge in computer vision. Further, possible blurring due to motion or wind and overlap between heads for dense populations make this task even more complex. Through a joint international collaborative effort, we have built a large, diverse and well-labelled dataset, the Global Wheat Head detection (GWHD) dataset. It contains 4,700 high-resolution RGB images and 190,000 labelled wheat heads collected from several countries around the world at different growth stages with a wide range of genotypes. Guidelines for image acquisition, associating minimum metadata to respect FAIR principles and consistent head labelling methods are proposed when developing new head detection datasets. The GWHD is publicly available at http://www.global-wheat.com/ and aimed at developing and benchmarking methods for wheat head detection.Comment: 16 pages, 7 figures, Dataset pape

    All-sky Search for High-Energy Neutrinos from Gravitational Wave Event GW170104 with the ANTARES Neutrino Telescope

    Full text link
    Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th^{\textrm{th}}, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the ANTARES neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within ±500\pm500 s around the GW event time nor any time clustering of events over an extended time window of ±3\pm3 months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than 4×1054\sim4\times 10^{54} erg for a E2E^{-2} spectrum
    corecore