1,721,448 research outputs found
Searching for tau neutrinos with Cherenkov telescopes
Full text linkCherenkov telescopes have the capability of detecting high energy tau neutrinos in the energy range of 1–1000 PeV by searching for very inclined showers. If a tau lepton, produced by a tau neutrino, escapes from the Earth or a mountain, it will decay and initiate a shower in the air which can be detected by an air shower fluorescence or Cherenkov telescope. In this paper, we present detailed Monte Carlo simulations of corresponding event rates for the VERITAS and two proposed Cherenkov Telescope Array sites: Meteor Crater and Yavapai Ranch, which use representative AGN neutrino flux models and take into account topographic conditions of the detector sites. The calculated neutrino sensitivities depend on the observation time and the shape of the energy spectrum, but in some cases are comparable or even better than corresponding neutrino sensitivities of the IceCube detector. For VERITAS and the considered Cherenkov Telescope Array sites the expected neutrino sensitivities are up to factor 3 higher than for the MAGIC site because of the presence of surrounding mountains
MAGIC as a high-energy ?t detector: Performance study to follow-up IceCube transient events
No full textMAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located on the Canary Island of La Palma and dedicated to the study of very high energy gamma rays above 30 GeV. MAGIC has recently demonstrated its capability as a neutrino detector, by exploiting the Earth-skimming technique. The neutrino-event selection has been studied by pointing the telescopes towards the sea a few degrees below the horizon, with no pre-defined source direction. An upper limit to the ?t flux was set. In this work, a follow-up strategy of given source directions is presented. This new approach is characterised by pointing to targets passing through the sea window observable with MAGIC and for which a trigger from dedicated neutrino observatories is issued with large significance. Above a few tens of PeV, the acceptance of MAGIC to ?t is considerably large and compelling results can be obtained for transient events of short duration. The performance of this new method is tested on a sample of data collected by pointing MAGIC for a few days from March to May 2016 towards the direction of a multi-PeV neutrino that IceCube detected on June 11th 2014 (reconstructed direction (J2000.0) RA: 110.34? and Dec.: 11.48?). A selection cut is studied in order to discriminate t-lepton-induced air showers from the background of very inclined cosmic-ray-induced air showers. An upper limit on the neutrino flux from the above given neutrino direction is presented
MAGIC as a high-energy ντ detector: performance study to follow-up IceCube transient events
No full textMAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located on the Canary Island of La Palma and dedicated to the study of very high energy gamma rays above 30 GeV. MAGIC has recently demonstrated its capability as a neutrino detector, by exploiting the Earth-skimming technique. The neutrino-event selection has been studied by pointing the telescopes towards the sea a few degrees below the horizon, with no pre-defined source direction. An upper limit to the ντ flux was set. In this work, a follow-up strategy of given source directions is presented. This new approach is characterised by pointing to targets passing through the sea window observable with MAGIC and for which a trigger from dedicated neutrino observatories is issued with large significance. Above a few tens of PeV, the acceptance of MAGIC to ντ is considerably large and compelling results can be obtained for transient events of short duration. The performance of this new method is tested on a sample of data collected by pointing MAGIC for a few days from March to May 2016 towards the direction of a multi-PeV neutrino that IceCube detected on June 11th 2014 (reconstructed direction (J2000.0) RA: 110.34◦ and Dec.: 11.48◦). A selection cut is studied in order to discriminate τ-lepton-induced air showers from the background of very inclined cosmic-ray-induced air showers. An upper limit on the neutrino flux from the above given neutrino direction is presented
Search for multi-flares of high energy neutrinos from Active Galactic Nuclei with the IceCube detector
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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