2121. Search for large-scale anisotropy on arrival directions of ultra-high-energy cosmic rays observed with the telescope array experimentR. U. Abbasi, Mitsuhiro Abe, T. Abu-Zayyad, M. Allen, R. Azuma, E. Barcikowski, J. W. Belz, Douglas R. Bergman, S. A. Blake, Jon Paul Lundquist, 2020, izvirni znanstveni članek Opis: Motivated by the detection of a significant dipole structure in the arrival directions of ultra-high-energy cosmic rays above 8 EeV reported by the Pierre Auger Observatory (Auger), we search for a large-scale anisotropy using data collected with the surface detector array of the Telescope Array Experiment (TA). With 11 yr of TA data, a dipole structure in a projection of the R.A. is fitted with an amplitude of 3.3% ± 1.9% and a phase of 131° ± 33°. The corresponding 99% confidence-level upper limit on the amplitude is 7.3%. At the current level of statistics, the fitted result is compatible with both an isotropic distribution and the dipole structure reported by Auger.
Ključne besede: cosmic rays, ultra-high-energy cosmic radiation, cosmic ray sources, cosmic ray showers, cosmic ray detectors, cosmic ray astronomy, extragalactic astronomy
Objavljeno v RUNG: 05.02.2021; Ogledov: 2426; Prenosov: 0
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2122. Evidence for a supergalactic structure of magnetic deflection multiplets of ultra-high-energy cosmic raysR. U. Abbasi, Mitsuhiro Abe, T. Abu-Zayyad, M. Allen, R. Azuma, E. Barcikowski, J. W. Belz, Douglas R. Bergman, S. A. Blake, 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 1019 eV using 7 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, because the supergalactic plane is a fit to the average matter density of the local large-scale structure, 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 the TA (the Hotspot and Coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data posttrial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.2σ. The 10 years of data posttrial significance is 4.1σ. 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: extragalactic magnetic fields, ultra-high-energy cosmic radiation, cosmic rays, high energy astrophysics, astrophysical magnetism, cosmic ray astronomy, cosmic ray sources
Objavljeno v RUNG: 05.02.2021; Ogledov: 2530; Prenosov: 126
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2123. Measurement of the proton-air cross section with Telescope Array's Black Rock Mesa and Long Ridge fluorescence detectors, and surface array in hybrid modeR. U. Abbasi, Mitsuhiro Abe, T. Abu-Zayyad, M. Allen, R. Azuma, E. Barcikowski, J. W. Belz, Douglas R. Bergman, S. A. Blake, Jon Paul Lundquist, 2020, izvirni znanstveni članek Opis: Ultra high energy cosmic rays provide the highest known energy source in the universe to measure proton cross sections. Though conditions for collecting such data are less controlled than an
accelerator environment, current generation cosmic ray observatories have large enough exposures to collect significant statistics for a reliable measurement for energies above what can be attained in the lab. Cosmic ray measurements of cross section use atmospheric calorimetry to measure depth of air shower maximum (Xmax), which is related to the primary particle’s energy and mass. The tail of the Xmax distribution is assumed to be dominated by showers generated by protons, allowing measurement of the inelastic proton-air cross section. In this work the proton-air inelastic
cross section measurement, σ_inel_p−air, using data observed by Telescope Array’s Black Rock Mesa and Long Ridge fluorescence detectors and surface detector array in hybrid mode is presented. σ_inel_p−air is observed to be 520.1 ± 35.8 [Stat.] +25.0 −40 [Sys.] mb at √s = 73 TeV. The total proton-proton cross section is subsequently inferred from Glauber formalism and is found to be σ_tot_pp = 139.4 +23.4−21.3[Stat.] +15.0−24.0[Sys.] mb.
Ključne besede: cosmic rays, astroparticles, proton-air cross section
Objavljeno v RUNG: 04.02.2021; Ogledov: 2378; Prenosov: 0
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2124. Observations of the origin of downward terrestrial gamma-ray flashesJ. W. Belz, P. R. Krehbiel, J. Remington, M. A. Stanley, R. U. Abbasi, R. LeVon, W. Rison, D. Rodeheffer, T. Abu-Zayyad, Jon Paul Lundquist, 2020, izvirni znanstveni članek Opis: In this paper we report the first close, high‐resolution observations of downward‐directed terrestrial gamma‐ray flashes (TGFs) detected by the large‐area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (IBPs) in the first few milliseconds of negative cloud‐to‐ground and low‐altitude intracloud flashes and that the IBPs are produced by a newly identified streamer‐based discharge process called fast negative breakdown. The observations indicate the relativistic runaway electron avalanches (RREAs) responsible for producing the TGFs are initiated by embedded spark‐like transient conducting events (TCEs) within the fast streamer system and potentially also by individual fast streamers themselves. The TCEs are inferred to be the cause of impulsive sub‐pulses that are characteristic features of classic IBP sferics. Additional development of the avalanches would be facilitated by the enhanced electric field ahead of the advancing front of the fast negative breakdown. In addition to showing the nature of IBPs and their enigmatic sub‐pulses, the observations also provide a possible explanation for the unsolved question of how the streamer to leader transition occurs during the initial negative breakdown, namely, as a result of strong currents flowing in the final stage of successive IBPs, extending backward through both the IBP itself and the negative streamer breakdown preceding the IBP.
Ključne besede: terrestrial gamma-ray flashes, lightning, fast breakdown, initial breakdown pulse, atmospheric electricity, transient conducting events
Objavljeno v RUNG: 04.02.2021; Ogledov: 2504; Prenosov: 21
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2125. |
2126. Post-Covid recovery of the Cultural and Creative Industries in the Adriatic-Ionian RegionPeter Purg, Dora Ruždjak Podolski, NIhad Kreševljaković, Sehad Čekić, Goran Tomka, Marija Katalinić, prispevek na konferenci brez natisa Ključne besede: recovery, art, innovation, culture, creative
Objavljeno v RUNG: 03.02.2021; Ogledov: 2232; Prenosov: 0
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2127. Photodegradation mechanisms of reactive blue 19 dye under UV and simulated solar light irradiationZeinab Ebrahimpour, Olena Pliekhova, Humberto Cabrera, Mahmoud Abdelhamid, Dorota Korte, Komlan Segbéya Gadedjisso-Tossou, Joseph J. Niemela, Urška Lavrenčič Štangar, Mladen Franko, 2021, izvirni znanstveni članek Ključne besede: reactive blue 19, photocatalytic, photosensitization, thermal lens, UV-Vis
Objavljeno v RUNG: 02.02.2021; Ogledov: 2530; Prenosov: 0
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2128. |
2129. Stoichiometry and disorder influence over electronic structure in nanostructured VO[sub]x filmsAlessandro D'Elia, S. J. Rezvani, Nicola Zema, F. Zuccaro, Mattia Fanetti, Blaž Belec, B. W. Li, C. W. Zou, Carlo Spezzani, Maurizio Sacchi, Augusto Marcelli, Marcello Coreno, 2021, izvirni znanstveni članek Ključne besede: nanoparticles, VOx films, electronic structure, nanostructured films
Objavljeno v RUNG: 31.01.2021; Ogledov: 2402; Prenosov: 0
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2130. Ezikov transfer v oblastta na pragmatikata : predavanje na Inštitutu za bolgarski jezik, Sofija, Bolgarija, 28. 1. 2021Penka Stateva, 2021, predavanje na tuji univerzi Opis: n this talk I will present work in progress that aims to explore a previously uncharted area of multilingual language acquisition, which concerns negative linguistic transfer in the domain of pragmatics. The research is part of a larger program in experimental pragmatics which aims to identify points of cross-linguistic diversion that affect meaning. We investigate the impact of language variation on bilingual acquisition of grammatical number in pairs of languages like Lebanese Arabic and French, and Slovenian-Italian, in which the interpretation of plural morphology within each pair is different depending on whether the number paradigm also includes dual number or not.
Ključne besede: negative transfer, plural interpretation, anti-duality, pragmatic enrichment
Objavljeno v RUNG: 29.01.2021; Ogledov: 2536; Prenosov: 0
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