Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


31 - 40 / 108
Na začetekNa prejšnjo stran12345678910Na naslednjo stranNa konec
31.
Expected performance of the AugerPrime Radio Detector
F. Schlüter, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The AugerPrime Radio Detector will significantly increase the sky coverage of mass-sensitive measurements of ultra-high energy cosmic rays with the Pierre Auger Observatory. The detection of highly inclined air showers with the world’s largest 3000km^2 radio-antenna array in coincidence with the Auger water-Cherenkov detector provides a clean separation of the electromagnetic and muonic shower components. The combination of these highly complementary measurements yields a strong sensitivity to the mass composition of cosmic rays. We will present the first results of an end-to-end simulation study of the performance of the AugerPrime Radio Detector. The study features a complete description of the AugerPrime radio antennas and reconstruction of the properties of inclined air showers, in particular the electromagnetic energy. The performance is evaluated utilizing a comprehensive set of simulated air showers together with recorded background. The estimation of an energy- and direction-dependent aperture yields an estimation of the expected 10-year event statistics. The potential to measure the number of muons in air showers with the achieved statistics is outlined. Based on the achieved energy resolution, the potential to discriminate between different cosmic-ray primaries is presented.
Ključne besede: Pierre Auger Observatory, AugerPrime, indirect detection, radio detection, radio antenna array, ultra-high energy, cosmic rays, air-shower muons, composition
Objavljeno v RUNG: 04.10.2023; Ogledov: 927; Prenosov: 6
.pdf Celotno besedilo (1,85 MB)
Gradivo ima več datotek! Več...

32.
First results from the AugerPrime Radio Detector
T. Fodran, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Observatory investigates the properties of the highest-energy cosmic rays with unprecedented precision. The aim of the AugerPrime upgrade is to improve the sensitivity to the primary particle type. The improved mass sensitivity is the key to exploring the origin of the highest-energy particles in the Universe. The purpose of the Radio Detector (as part of AugerPrime) is to extend the sensitivity of the mass measurements to zenith angles in the range from 65° to 85°. A radio antenna, sensitive in two polarization directions and covering a bandwidth from 30 to 80 MHz, will be added to each of the 1661 surface detector stations over the full 3000 km^2 area, forming the world’s largest radio array for the detection of cosmic particles. Since November 2019, an engineering array comprised of ten stations has been installed in the field. The radio antennas are calibrated using the Galactic (diffuse) emission. The sidereal modulation of this signal is monitored continuously and is used to obtain an end-to-end calibration from the receiving antenna to the ADC in the read-out electronics. The calibration method and first results will be presented. The engineering array is also fully integrated in the data acquisition of the Observatory and records air showers regularly. The first air showers detected simultaneously with the water-Cherenkov detectors and the Radio Detectors will be presented. Simulations of the detected showers, based on the reconstructed quantities, have been conducted with CORSIKA/CoREAS. A comparison of the measured radio signals with those predicted by simulations exhibits satisfying agreement.
Ključne besede: Pierre Auger Observatory, AugerPrime, indirect detection, radio detection, radio antenna array, surface detection, ground array, ultra-high energy, cosmic rays, galactic radio emission
Objavljeno v RUNG: 04.10.2023; Ogledov: 924; Prenosov: 6
.pdf Celotno besedilo (1,62 MB)
Gradivo ima več datotek! Več...

33.
Update on the large-scale cosmic-ray anisotropy search at the highest energies by the Telescope Array Experiment
T. Fujii, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The study of large-scale anisotropy at the highest energies is essential for understanding the transition from cosmic rays of galactic origin to those of extra-galactic origin, along with the magnetic fields in the galaxy and those beyond. Motivated by a significant detection of the large-scale anisotropy above 8 EeV by the Pierre Auger Observatory (Auger), we had previously reported, using 11 years of Telescope Array (TA) surface array data, a result compatible both with that of Auger, and with an isotropic source distribution [R. U. Abbasi et al., Astrophys. J. Lett. 898, L28 (2020)]. In this contribution, we will show the preliminary updated results using 12 years TA SD data to search for the large-scale anisotropy at the highest energies.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, anisotropy, large-scale, dipole
Objavljeno v RUNG: 04.10.2023; Ogledov: 1001; Prenosov: 4
.pdf Celotno besedilo (1,95 MB)
Gradivo ima več datotek! Več...

34.
UHECR mass composition from anisotropy of their arrival directions with the Telescope Array SD
M. Kuznetsov, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: We propose a new method for the estimation of ultra-high energy cosmic ray (UHECR) mass composition from a distribution of their arrival directions. The method employs a test statistic (TS) based on a characteristic deflection of UHECR events with respect to the distribution of luminous matter in the local Universe modeled with a flux-weighed 2MRS catalog. Making realistic simulations of the mock UHECR sets, we show that this TS is robust to the presence of galactic and non-extreme extra-galactic magnetic fields and sensitive to the mass composition of events in a set. We apply the method to Telescope Array surface detector data for 11 years and derive new independent constraints on fraction of protons and iron in p-Fe mix at E>10 EeV. At 10100 EeV --- pure iron or even more massive composition. This result is in tension with Auger composition model inferred from spectrum-Xmax fit at 2.7σ (2.0σ) for PT'11 (JF'12) regular GMF model.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, composition, anisotropy, magnetic fields, 2MRS
Objavljeno v RUNG: 04.10.2023; Ogledov: 1031; Prenosov: 5
.pdf Celotno besedilo (3,02 MB)
Gradivo ima več datotek! Več...

35.
Measurement of the Proton-Air Cross Section with Telescope Arrays Black Rock, Long Ridge, and Surface Array in Hybrid Mode.
R. Abbasi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Ultra High Energy Cosmic Ray (UHECR) detectors have been reporting on the proton-air cross section measurement beyond the capability of particle accelerators since 1984. The knowledge of this fundamental particle property is vital for our understanding of high energy particle interactions and could possibly hold the key to new physics. The data used in this work was collected over eight years using the hybrid events of Black Rock (BR) and Long Ridge (LR) fluorescence detectors as well as the Telescope Array Surface Detector (TASD). The proton-air cross section is determined at s√=73~TeV by fitting the exponential tail of the Xmax distribution of these events. The proton-air cross section is then inferred from the exponential tail fit and from the most updated high energy interaction models. σ^inel_p−air is observed to be 520.1±35.8 [Stat.] +25.3−42.9 [Sys.] mb. This is the second proton-air cross section work reported by the Telescope Array collaboration.
Ključne besede: Telescope Array, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, Xmax, proton-air cross-section, high energy particle interaction
Objavljeno v RUNG: 04.10.2023; Ogledov: 1051; Prenosov: 4
.pdf Celotno besedilo (1,47 MB)
Gradivo ima več datotek! Več...

36.
Observation of Variations in Cosmic Ray Shower Rates During Thunderstorms and Implications for Large-Scale Electric Field Changes
R. Abbasi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: This work presents the first observation by the Telescope Array Surface Detector (TASD) of the effect of thunderstorms on the development of the cosmic ray showers. Observations of variations in the cosmic ray showers, using the TASD, allows us to study the electric field inside thunderstorms on a large scale without dealing with all the limitation of narrow exposure in time and space using balloons and aircraft detectors. In this work, observations of variations in the cosmic ray shower intensity (ΔN/N) using the TASD, was studied and found to be on average at the (1−2)% level. These observations where found to be both negative and positive in polarity. They were found to be correlated with lightning but also with thunderstorms. The size of the footprint of these variations on the ground ranged from (4-24) km in diameter and lasted for 10s of minutes. Dependence of (ΔN/N) on the electric field inside thunderstorms, in this work, is derived from CORSIKA simulations.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, shower profile, lightning, atmospheric electric fields
Objavljeno v RUNG: 04.10.2023; Ogledov: 854; Prenosov: 5
.pdf Celotno besedilo (4,65 MB)
Gradivo ima več datotek! Več...

37.
Mass composition anisotropy with the Telescope Array Surface Detector data
Y. Zhezher, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Mass composition anisotropy is predicted by a number of theories describing sources of ultra-high-energy cosmic rays. Event-by-event determination of a type of a primary cosmic-ray particle is impossible due to large shower-to-shower fluctuations, and the mass composition usually is obtained by averaging over some composition-sensitive observable determined independently for each extensive air shower (EAS) over a large number of events. In the present study we propose to employ the observable ξ used in the TA mass composition analysis for the mass composition anisotropy analysis. The ξ variable is determined with the use of Boosted Decision Trees (BDT) technique trained with the Monte-Carlo sets, and the ξ value is assigned for each event, where ξ=1 corresponds to an event initiated by the primary iron nuclei and ξ=−1 corresponds to a proton event. Use of ξ distributions obtained for the Monte-Carlo sets allows us to separate proton and iron candidate events from a data set with some given accuracy and study its distributions over the observed part of the sky. Results for the TA SD 11-year data set mass composition anisotropy will be presented.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, composition, anisotropy, machine learning, boosted decision tree
Objavljeno v RUNG: 04.10.2023; Ogledov: 884; Prenosov: 5
.pdf Celotno besedilo (1,14 MB)
Gradivo ima več datotek! Več...

38.
The measurements of the cosmic ray energy spectrum and the depth of maximum shower development of Telescope Array Hybrid trigger events
H. Shin, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Telescope Array experiment is an ultra-high energy cosmic ray observatory located in Millard County, Utah, USA. The observatory consists of 3 fluorescence detector (FD) stations and 507 surface detectors (SD) that cover an area of ~700 km^2. Hybrid trigger is an external trigger system for the SD arrays that prompts the SD to perform data acquisition when an FD detects a shower-like event. In comparison with the SD autonomous trigger, hybrid trigger allows the SD to collect the data of an air shower that has primary energy below 10^18.5 eV, where the efficiency of SD autonomous trigger decreases rapidly. We present the measurements of the cosmic ray energy spectrum and the depth of maximum shower development of hybrid trigger events observed from October 2010 to September 2014.
Ključne besede: Telescope Array, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 04.10.2023; Ogledov: 931; Prenosov: 5
.pdf Celotno besedilo (1,35 MB)
Gradivo ima več datotek! Več...

39.
Cosmic-ray mass composition with the TA SD 12-year data
Y. Zhezher, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Telescope Array (TA) is the largest ultra-high-energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. It is dedicated to detect extensive air showers (EAS) in hybrid mode, both by measuring the shower’s longitudinal profile with fluorescence telescopes and their particle footprint on the ground from the surface detector (SD) array. While fluorescence telescopes can measure the most composition-sensitive characteristic of EAS, the depth of the shower maximum (\xmax), they also have the drawback of small duty cycle. This work aims to study the UHECR composition based solely on the surface detector data. For this task, a set of composition-sensitive observables obtained from the SD data is used in a machine-learning method -- the Boosted Decision Trees. We will present the results of the UHECR mass composition based on the 12-year data from the TA SD using this technique, and we will discuss of the possible systematics imposed by the hadronic interaction models.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, composition, machine learning, boosted decision tree
Objavljeno v RUNG: 04.10.2023; Ogledov: 879; Prenosov: 7
.pdf Celotno besedilo (763,42 KB)
Gradivo ima več datotek! Več...

40.
The ultra-high-energy cosmic-ray sky above 32 EeV viewed from the Pierre Auger Observatory
J. Biteau, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The region of the toe in the cosmic-ray spectrum, located at about 45 EeV by the Pierre Auger Collaboration, is of primary interest in the search for the origin of ultra-high energy cosmic rays (UHECRs). The suppression of the flux with increasing energy can be explained by the interaction of UHECRs with intergalactic photons, resulting in a shrinking of the observable universe, and/or by cut-offs in acceleration potential at the astrophysical sources, yielding a high-rigidity sample of single (or few) UHECR species around the toe. The predominance of foreground sources combined with reduced deflections could thus offer a path towards localizing ultra-high energy accelerators, through the study of UHECR arrival directions. In this contribution, we present the results of blind and astrophysically-motivated searches for anisotropies with data collected above 32 EeV during the first phase of the Pierre Auger Observatory, i.e. prior to the AugerPrime upgrade, for an exposure of over 120,000 km^2 yr sr. We have conducted model-independent searches for overdensities at small and intermediate angular scales, correlation studies with several astrophysical structures, and cross-correlation analyses with catalogs of candidate extragalactic sources. These analyses provide the most important evidence to date for anisotropy in UHECR arrival directions around the toe as measured from a single observatory.
Ključne besede: Pierre Auger Observatory, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, anisotropy, overdensities, hotspot, source correlation, cross-correlation
Objavljeno v RUNG: 04.10.2023; Ogledov: 874; Prenosov: 6
.pdf Celotno besedilo (2,15 MB)
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.05 sek.
Na vrh