2931. Še več elektrike, še več omrežjaDrago Papler, 2018, predgovor, uvodnik, spremna beseda Ključne besede: energetski sistemi, elektroenergetika, električna energija, omrežja, razvoj, tehnologije, kakovost, oskrba, zanesljivost, monitoring, regulacija, obnovljivi viri, sistemske storitve, odjemalci, izobraževanje, kadri
Objavljeno v RUNG: 19.05.2020; Ogledov: 2436; Prenosov: 0 |
2932. Evidence for a Supergalactic Structure of Magnetic Deflection Multiplets of Ultra-High Energy Cosmic RaysR. Abbasi, Jon Paul Lundquist, 2020, izvirni znanstveni članek Opis: Evidence for a large-scale supergalactic cosmic ray multiplet (arrival directions correlated with energy) structure is reported for ultra-high energy cosmic ray (UHECR) energies above 10^19 eV using seven years of data from the Telescope Array (TA) surface detector and updated to 10 years. Previous energy-position correlation studies have made assumptions regarding magnetic field shapes and strength, and UHECR composition. Here the assumption tested is that, since the supergalactic plane is a fit to the average matter density of the local Large Scale Structure (LSS), UHECR sources and intervening extragalactic magnetic fields are correlated with this plane. This supergalactic deflection hypothesis is tested by the entire field-of-view (FOV) behavior of the strength of intermediate-scale energy-angle correlations. These multiplets are measured in spherical cap section bins (wedges) of the FOV to account for coherent and random magnetic fields. The structure found is consistent with supergalactic deflection, the previously published energy spectrum anisotropy results of TA (the hotspot and coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data post-trial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.19σ. The ten years of data post-trial significance is 4.09σ. Furthermore, the starburst galaxy M82 is shown to be a possible source of the TA Hotspot, and an estimate of the supergalactic magnetic field using UHECR measurements is presented.
Ključne besede: astroparticle physics, cosmic rays, UHECR, supergalactic plane, multiplets, magnetic deflection, large-scale structure of universe
Objavljeno v RUNG: 19.05.2020; Ogledov: 2792; Prenosov: 0
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2933. New air fluorescence detectors employed in the Telescope Array experimentH. Tokuno, Jon Paul Lundquist, 2012, izvirni znanstveni članek Opis: Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The experiment includes a surface detector (SD) array and three fluorescence detector (FD) stations. The FD stations, installed surrounding the SD array, measure the air fluorescence light emitted from extensive air showers (EASs) for precise determination of their energies and species. The detectors employed at one of the three FD stations were relocated from the High Resolution Fly's Eye (HiRes) experiment. At the other two stations, newly designed detectors were constructed for the TA experiment. An FD consists of a primary mirror and a camera equipped with photomultiplier tube pixels. To obtain the EAS parameters with high accuracy, understanding the FD optical characteristics is important. In this paper, we report the characteristics and installation of the new FDs and the performances of the FD components. The results of the monitored mirror reflectance during the observation time are also described in this report.
Ključne besede: Ultra high energy cosmic rays, Extensive air showers, Air fluorescence light detectors
Objavljeno v RUNG: 19.05.2020; Ogledov: 2517; Prenosov: 0
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2934. CORSIKA Simulation of the Telescope Array Surface DetectorT. Abu-Zayyad, Jon Paul Lundquist, 2014, izvirni znanstveni članek Opis: The Telescope Array is the largest experiment studying ultra-high energy cosmic rays in the northern hemisphere. The detection area of the experiment consists of an array of 507 surface detectors, and a fluorescence detector divided into three sites at the periphery. The viewing directions of the 38 fluorescence telescopes point over the air space above the surface array. In this paper, we describe a technique that we have developed for simulating the response of the array of surface detectors of the Telescope Array experiment. The two primary components of this method are (a) the generation of a detailed CORSIKA Monte Carlo simulation with all known characteristics of the data, and (b) the validation of the simulation by a direct comparison with the Telescope Array surface detector data. This technique allows us to make a very accurate calculation of the acceptance of the array. We also describe a study of systematic uncertainties in this acceptance calculation.
Ključne besede: cosmic ray, extensive air shower, simulation, surface detector
Objavljeno v RUNG: 19.05.2020; Ogledov: 2514; Prenosov: 0
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2935. Search for anisotropy of ultrahigh energy cosmic rays with the Telescope Array experimentT. Abu-Zayyad, Jon Paul Lundquist, 2012, izvirni znanstveni članek Opis: We study the anisotropy of Ultra-High Energy Cosmic Ray (UHECR) events collected by the Telescope Array (TA) detector in the first 40 months of operation. Following earlier studies, we examine event sets with energy thresholds of 10 EeV, 40 EeV, and 57 EeV. We find that the distributions of the events in right ascension and declination are compatible with an isotropic distribution in all three sets. We then compare with previously reported clustering of the UHECR events at small angular scales. No significant clustering is found in the TA data. We then check the events with E > 57 EeV for correlations with nearby active galactic nuclei. No significant correlation is found. Finally, we examine all three sets for correlations with the large-scale structure (LSS) of the universe. We find that the two higher-energy sets are compatible with both an isotropic distribution and the hypothesis that UHECR sources follow the matter distribution of the universe (the LSS hypothesis), while the event set with E > 10 EeV is compatible with isotropy and is not compatible with the LSS hypothesis at 95% CL unless large deflection angles are also assumed. We show that accounting for UHECR deflections in a realistic model of the Galactic magnetic field can make this set compatible with the LSS hypothesis.
Ključne besede: acceleration of particles, astroparticle physics, cosmic rays, magnetic fields, methods: statistical, relativistic processes
Objavljeno v RUNG: 19.05.2020; Ogledov: 2899; Prenosov: 0
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2936. The surface detector array of the Telescope Array experimentT. Abu-Zayyad, Jon Paul Lundquist, 2012, izvirni znanstveni članek Opis: The Telescope Array (TA) experiment, located in the western desert of Utah, USA, is designed for the observation of extensive air showers from extremely high energy cosmic rays. The experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection of shower particles at ground level and fluorescence photons along the shower track. The TA surface detectors and fluorescence detectors started full hybrid observation in March, 2008. In this article we describe the design and technical features of the TA surface detector.
Ključne besede: Ultra-high energy cosmic rays, Telescope Array experiment, Extensive air shower array
Objavljeno v RUNG: 19.05.2020; Ogledov: 2723; Prenosov: 0
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2937. The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular modeT. Abu-Zayyad, Jon Paul Lundquist, 2013, izvirni znanstveni članek Opis: We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array’s third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array’s middle drum detector and the direct comparison to the high resolution fly’s eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.
Ključne besede: UHECR, Energy spectrum, Fluorescence, Monocular
Objavljeno v RUNG: 19.05.2020; Ogledov: 2555; Prenosov: 0
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2938. Correlations of the arrival directions of ultra-high energy cosmic ray with extragalactic objects as observed by the telescope array experimentT. Abu-Zayyad, Jon Paul Lundquist, 2013, izvirni znanstveni članek Opis: We search for correlations between the positions of extragalactic objects and the arrival directions of ultra-high energy cosmic rays (UHECRs) with primary energy E ≥ 40 EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examine several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We count the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine the combination of these parameters that maximizes the correlations, and we calculate the probability of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.
Ključne besede: acceleration of particles, astroparticle physics, cosmic rays
Objavljeno v RUNG: 19.05.2020; Ogledov: 2873; Prenosov: 125
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