31. 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: 2724; Prenosov: 0
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32. Supergalactic Structure of Multiplets with the Telescope Array Surface DetectorJon Paul Lundquist, P. Sokolsky, 2019, objavljeni znanstveni prispevek na konferenci Opis: Evidence of supergalactic structure of multiplets has been found for ultra-high energy cosmic rays (UHECR) with energies above 10^19 eV using 7 years of data from the Telescope Array (TA) surface detector. The tested hypothesis is that UHECR sources, and intervening magnetic fields, may be correlated with the supergalactic plane, as it is a fit to the average matter density within the GZK horizon. This structure is measured by the average behavior of the strength of intermediate-scale correlations between event energy and position (multiplets). These multiplets are measured in wedge-like shapes on the spherical surface of the fieldof-view to account for uniform and random magnetic fields. The evident structure found is consistent with toy-model simulations of a supergalactic magnetic sheet and the previously published Hot/Coldspot results of TA. The post-trial probability of this feature appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be ~4.5σ.
Ključne besede: UHECR, cosmic rays, energy spectrum, anisotropy, large-scale structure, magnetic deflection
Objavljeno v RUNG: 28.04.2020; Ogledov: 2790; Prenosov: 149
 Celotno besedilo (1,38 MB) |
33. Supergalactic Structure of Energy-Angle CorrelationsJon Paul Lundquist, P. Sokolsky, 2020, objavljeni znanstveni prispevek na konferenci Opis: Evidence for the supergalactic structure of multiplets (energy-angle correlations) has previously been shown using ultra-high energy cosmic ray (UHECR) data from Telescope Array (TA) with energies above 10^19 eV. The supergalactic deflection hypothesis (that UHECR sources and intervening magnetic fields are correlated) is measured by the all-sky behavior of the strength of
intermediate-scale correlations. The multiplets are measured in spherical surface wedge bins of the field-of-view to account for uniform and random magnetic fields. The structure found is consistent with the previously published energy spectrum anisotropy results of TA and toy-model simulations of a supergalactic magnetic sheet. The 7 year data post-trial significance of this feature appearing by chance, on an isotropic sky, was found by Monte Carlo simulation to be ∼4σ. The analysis has now been applied to 10 years of data.
Ključne besede: Cosmic rays, UHECR, energy spectrum, magnetic deflection, large-scale structure, supergalactic, multiplets
Objavljeno v RUNG: 27.04.2020; Ogledov: 2659; Prenosov: 85
Celotno besedilo (1,66 MB) |
34. Evidence of Intermediate-scale Energy Spectrum Anisotropy of Cosmic Rays E ≥ 10^19.2 eV with the Telescope Array Surface DetectorR.U. Abbasi, Jon Paul Lundquist, 2018, izvirni znanstveni članek Opis: Evidence for an intermediate-scale energy spectrum anisotropy has been found in the arrival directions of ultra-high energy cosmic rays for energies greater than 10^19.2 eV in the northern hemisphere using 7 years of Telescope Array surface detector data. A relative energy distribution test is done comparing events inside oversampled spherical caps of equal exposure, to those outside, using the Poisson likelihood ratio. The center of maximum significance is at 9h16m, 45°, and has a deficit of events with energies 10^19.2 ≤ E < 10^19.75 eV and an excess for E ≥ 10^19.75 eV. The post-trial probability of this energy anisotropy, appearing by chance anywhere on an isotropic sky, is found by Monte Carlo simulation to be 9 × 10−5 (3.74σ global).
Ključne besede: astroparticle physics, cosmic rays, anisotropy, large-scale structure of universe
Objavljeno v RUNG: 24.04.2020; Ogledov: 2949; Prenosov: 196
Celotno besedilo (1,43 MB) |
35. Indications of Intermediate-Scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array ExperimentR.U. Abbasi, Jon Paul Lundquist, 2014, izvirni znanstveni članek Opis: We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 year period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20∘-radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A.=146.7∘, Dec.=43.2∘. The position of the hotspot is about 19∘ off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7×10−4 (3.4σ).
Ključne besede: acceleration of particles, cosmic rays, large-scale structure of universe, surveys
Objavljeno v RUNG: 24.04.2020; Ogledov: 2999; Prenosov: 0
Gradivo ima več datotek! Več... |
36. Interplay among Work Function, electronic structure and stoichiometry in nanostructured VOx films2020, izvirni znanstveni članek Opis: The work function is the parameter of greatest interest in many technological applications involving charge exchange
mechanisms at the interface. The possibility to produce samples with a controlled work function is then particularly
interesting, albeit challenging. We synthetized nanostructured vanadium oxide films by a room temperature Supersonic
Cluster Beam Deposition method, obtaining samples with tunable stoichiometry and work function (3.7-7 eV). We present
an investigation of the electronic structure of several vanadium oxide films as a function of the oxygen content via in-situ
Auger, valence-band photoemission spectroscopy and work function measurements. The experiments probed the partial 3d
density of states, highlighting the presence of strong V3d-O2p and V3d-V4s hybridization which influence 3d occupation. We
show how controlling the stoichiometry of the sample implies control over work function, and that the access to nanoscale
quantum confinement can be exploited to increase the work function of the sample relative to the bulk analogue. In general,
the knowledge of the interplay among work function, electronic structure, and stoichiometry is strategic to match
nanostructured oxides to their target applications
Ključne besede: work function, VOx, Electronic structure, nanostructured films
Objavljeno v RUNG: 24.02.2020; Ogledov: 2563; Prenosov: 0
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37. A Generalization of Semidetached Subalgebras in BCK∕BCI-algebrasHashem Bordbar, Mohammad Rahim Bordbar, Young Bae Jun, 2019, izvirni znanstveni članek Opis: Generalization of the paper [Y. B. Jun and S. Z. Song, Semidetached subalgebras in BCK∕BCI-algebras, to appear in Bulletin of the Korean Mathematical Society] is discussed. Several conditions for a semidetached structure in BCK∕BCI-algebras to be a semidetached subalgebra are provided. The concepts of (∈¯,∈¯∨qk¯)-fuzzy subalgebra, k-left (k-right) (qk,∈∨qk)-fuzzy subalgebra, (qk¯,∈¯∨qk¯)-fuzzy subalgebra and (∈¯∨qk¯,∈¯∨qk¯)-fuzzy subalgebra are introduced, and relative relations and properties are discussed.
Ključne besede: ð2, 2_qkÞ-fuzzy subalgebra, k-left (k-right) ðqk, 2_qkÞ-fuzzy subalgebra, ð 2 _ qk, 2 _ qk Þ-fuzzy subalgebra, semidetached structure, semidetached subalgebra.
Objavljeno v RUNG: 02.12.2019; Ogledov: 2761; Prenosov: 0
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40. Regional biodiversity and seasonal dynamics of the bacterial communities in karstic springs of SloveniaMaja Opalički Slabe, 2019, doktorska disertacija Opis: Information on groundwater’s natural bacterial communities is important for evaluating pristine groundwater’s quality, as environmental changes potentially lead to alterations in bacterial community structures. In four seasons, 15 hypothetically pristine springs across five karst eco-regions in Slovenia (Central Europe) were analysed during their low discharge, and their basic physical and chemical parameters were recorded. The diversity of bacterial community structures was assessed with a terminal restriction fragment length polymorphism fingerprinting method. Total cell counts as bacterial abundance and electron transport system activity as bacterial respiratory activity were used for quantitative evaluation of bacterial communities. To detect anthropogenic pollution, spring water was tested by the cultivation of coliform bacteria and Escherichia coli (E. coli).
Results indicate distinct regional differences in environmental parameters, bacterial respiratory activity, presence of coliforms and E. coli, bacterial abundances, and qualitative bacterial community structures, but there were no regional differences in the numbers of operational taxonomic units and biodiversity indices (Shannon-Wiener’s and Simpson’s diversity index, Buzas and Gibson’s evenness). The analysis of seasonal environmental parameters showed significant differences in dissolved organic carbon and pH, and also significant changes in bacterial respiratory activity and abundances, as well as differences in bacterial community structures, the numbers of operational taxonomic units, and biodiversity indices. No seasonal variations were shown for coliforms and E. coli.
Despite seasonal oscillations, regional differences prevailed among five karst eco-regions and indicate a significant influence on the qualitative and quantitative aspects of groundwater bacterial community structures. The study confirmed both regional and seasonal differences in groundwater bacterial community structures, which should be included in further sustainable management plans of the aquifers.
Ključne besede: karst springs, bacterial community structure (BCS), terminal restriction fragment length polymorphism (T-RFLP), total cell counts (TCC), electron transport system activity (ETSA)
Objavljeno v RUNG: 26.06.2019; Ogledov: 3771; Prenosov: 184
Celotno besedilo (3,76 MB) |
