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1.
Highlights from the Telescope Array Experiment
J. Kim, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci (vabljeno predavanje)

Opis: The Telescope Array (TA) is the largest ultra-high energy cosmic ray (UHECR) observatory in the Northern Hemisphere. Together with the TA Low Energy Extension (TALE), TA×4, and TALE infill detector, the TA measures the properties of UHECR-induced extensive air showers (EAS) in the energy region from 10^15 eV to over 10^20 eV. Each of these uses a hybrid system with an array of scintillators to sample the footprint of the EAS at the Earth’s surface along with telescopes that measure the fluorescence and Cherenkov light from the EAS. The statistics at the highest energies are being enhanced with the TA×4 detector, half completed but still under construction, which will quadruple the surface detector area with telescopes. The TALE infill surface detectors were recently deployed to further lower the hybrid energy threshold of TALE. We present the status of the experiment and recent results on the energy spectrum, mass composition, and anisotropy, including new features in the energy spectrum at about 10^19.2 eV and in the UHECR arrival direction anisotropy.
Ključne besede: Telescope Array, TALE, low energy extension, TAx4, indirect detection, hybrid detection, ground array, surface detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum, composition, anisotropy
Objavljeno v RUNG: 10.10.2023; Ogledov: 278; Prenosov: 6
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2.
Effect of optical properties of FDs on reconstruction analysis
D. Sato, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The TA experiment uses fluorescence telescopes to observe cosmic ray air showers. The telescope camera uses PMTs as Pixels. The telescope’s PMT pointing direction has an uncertainty of 0.1°, and more precise measurements of the telescope's optical properties are needed to more accurately reconstruct the cosmic ray air showers. We have developed the Opt-copter which is a light source mounted on a drone that can be flown within the telescope's field of view. Observational experiments with the Opt-copter have provided a more accurate analysis of the telescope viewing direction. In this study, we estimate the effect of this measurement of accurate telescope viewing direction on the reconstruction of cosmic ray air showers.
Ključne besede: Telescope Array, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, composition, calibration, Xmax
Objavljeno v RUNG: 10.10.2023; Ogledov: 274; Prenosov: 6
.pdf Celotno besedilo (670,84 KB)
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3.
Effects of atmospheric transparency on TA air shower analysis
K. Mizuno, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The Telescope Array (TA) experiment continues to observe Ultra High Energy Cosmic Rays (UHECRs) both with its original TA detectors as well as with the new TAx4 expansion detectors. These observations employ Fluorescence Detectors (FDs) to capture the air shower induced by the primary UHECRs. The FD observes fluorescence light emitted from atmospheric nitrogen molecules excited by air shower particles. Observation of the FD extends over tens of kilometers, and the fluorescence light is attenuated by scattering from atmospheric molecules and aerosols during the propagation process. Seasonal dependence was found when evaluating the attenuation of fluorescence by aerosols. We will report on the effects of this seasonal dependence on TA air shower analysis.
Ključne besede: Telescope Array, TAx4, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, atmosphere, calibration, VAOD
Objavljeno v RUNG: 10.10.2023; Ogledov: 282; Prenosov: 6
.pdf Celotno besedilo (1,16 MB)
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4.
Measurement of cosmic-ray energy spectrum with the TALE detector in hybrid mode
H. Oshima, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The TA Low-energy Extension (TALE) experiment extends the low-energy side of the TA experiment below 10^15 eV. A main objective of TALE is to study the transition from galactic to extragalactic cosmic rays. The TALE detector is a hybrid observatory composed of fluorescence telescopes and a surface detector array of scintillation counters. The surface detectors are arranged with inter-counter spacing of 400 and 600 meters, suitable for hybrid energy spectrum measurements in the low-energy region. We measured the energy spectrum using data collected during 429 hours of observation by the TALE hybrid detector. This energy spectrum measurement will play an important role in understanding the transition from cosmic rays of galactic origin to those of extragalactic origin.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, hybrid detection, ground array, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum
Objavljeno v RUNG: 10.10.2023; Ogledov: 250; Prenosov: 4
.pdf Celotno besedilo (3,33 MB)
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5.
Systematic uncertainty in the analysis of the TA fluorescence detector from fluorescence yield models
K. Komori, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: Ultra-high energy cosmic rays have been observed by various experiments such as Telescope Array (TA) and the Pierre Auger Observatory (Auger). There are differences in the energy spectra measured by TA and Auger. One reason for this difference is systematic uncertainty in the energy determination. The fluorescence yield model, which consists of fluorescence emission efficiencies and spectra, is one of the most significant components of this systematic uncertainty. Fluorescence emission efficiencies and spectra have been measured in various experiments, and different measurements are currently used to determine the energy of the TA and Auger experiments. In this study, we estimate the influence of the fluorescence yield model on the systematic uncertainty in the energy determination of the TA fluorescence detector.
Ključne besede: Telescope Array, indirect detection, fluorescence detection, fluorescence yield, ultra-high energy, cosmic rays, energy uncertainty
Objavljeno v RUNG: 09.10.2023; Ogledov: 259; Prenosov: 5
.pdf Celotno besedilo (942,98 KB)
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6.
Monocular and Hybrid Analysis for TA×4 Fluorescence Detectors
Y. Kusumori, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The TA×4 project is an extension of the Telescope Array (TA) experiment, aimed at clarifying the origin of the highest energy cosmic rays. It has deployed 4 fluorescence detectors (FDs) and 130 surface detectors (SDs) at the northeast lobe of the original TA array and 8 FDs and 127 SDs at the southeast lobe of the original TA array, expanding the detection area about four times larger than the TA experiment. This expansion enables us to sample larger data. The TA×4 has been collecting data to obtain solid evidence of the excess of events in the arrival direction distribution, known as the TA hotspot, reported in 2014 by the TA experiment. The north and south observations began in 2018 and 2019, respectively, and are ongoing except for a hiatus from February to June 2020 due to the COVID-19 pandemic. In this presentation, we will report the details of TA×4 FD monocular analysis.
Ključne besede: Telescope Array, TAx4, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 09.10.2023; Ogledov: 299; Prenosov: 6
.pdf Celotno besedilo (3,20 MB)
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7.
Cosmic ray energy spectrum and mass composition with the TALE fluorescence detector
T. AbuZayyad, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The Telescope Array (TA) cosmic rays detector located in the State of Utah in the United States is the largest ultra high energy cosmic rays detector in the northern hemisphere. The Telescope Array Low Energy Extension (TALE) fluorescence detector (FD) was added to TA in order to lower the detector's energy threshold, and has succeeded in measuring the cosmic rays energy spectrum down to PeV energies, by making use of the direct Cherenkov light produced by air showers. In this contribution we present the results of a measurement of the cosmic-ray energy spectrum and mass composition using TALE FD data collected over a period of ∼8 years. This contribution provides an update to results on the cosmic-ray energy spectrum and mass composition presented at this conference in 2021. The update includes data collected during 16 additional months of observation and an updated detector simulation sets.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 09.10.2023; Ogledov: 244; Prenosov: 5
.pdf Celotno besedilo (363,14 KB)
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8.
A study of the systematic effects on the energy scale for the measurement of UHECR spectrum by the TA SD array
K. Fujita, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci

Opis: We evaluated the systematic deviation of energy scales for the energy spectrum of the highest energy cosmic rays observed by the Telescope Array Surface Detector array due to differences in atmospheric fluorescence yield and missing energy estimation. The energy dependence on the energy scales is also investigated and observationally confirmed by the constant intensity cut method analysis. The results of these studies will be presented.
Ključne besede: Telescope Array, indirect detection, surface detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, energy spectrum, fluorescence yield, missing energy, systematics
Objavljeno v RUNG: 09.10.2023; Ogledov: 331; Prenosov: 4
.pdf Celotno besedilo (867,73 KB)
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9.
Cosmic ray mass composition measurement with the TALE hybrid detector
K. Fujita, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: We report on the cosmic ray mass composition measured by the Telescope Array Low-energy Extension (TALE) hybrid detector. The TALE detector consists of a Fluorescence Detector (FD) station with 10 FD telescopes located at the TA Middle Drum FD Station (itself made up of 14 FD telescopes), and a Surface Detector (SD) array of scintillation counters. The SD array consists of 40 counters with 400 m spacing and 40 counters with 600 m spacing. The FD station, with a total of 24 telescopes, overlooks the SD array and provides sky coverage with an elevation angle range of 3∘ to 59∘. In this contribution, we will present the latest result of the cosmic ray mass composition measurement in the energy range from 10^16.5 eV to 10^18.5 eV using almost 5 years of TALE hybrid data.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, hybrid detection, ground array, infill array, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, composition
Objavljeno v RUNG: 09.10.2023; Ogledov: 271; Prenosov: 6
.pdf Celotno besedilo (1,94 MB)
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10.
Telescope Array Cloud Ranging Test
T. Okuda, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Telescope Array (TA) experiment detects air-showers induced by ultra high energy cosmic rays. The TA atmospheric Fluorescence telescopic Detector(TAFD) observes cosmic ray airshower, which is incident very far from the telescope. The observation does not take place in overcast night. However, the cloud status changes quickly and sometimes there are some isolated clouds. If the cloud is behind the airshower as viewed from the TAFD, the cloud presents no problem for airshower reconstruction. However if the cloud obscures the airshower, it does create a problem for airshower reconstruction. The problematic event can be rejected by airshower profile at reconstruction. However, the estimation of exposure with isolated cloud is difficult. And it should be affected more at higher energy event with relatively further from the telescope, which is lower statistics and more important for the ultra high energy cosmic ray physics. Therefore, to test the method for evaluating the correction of exposure, we installed stereo cloud cameras near one of FD sites. I report the status of the study of the Telescope Array Cloud Ranging Test.
Ključne besede: Telescope Array, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, atmosphere, cloud detection, exposure, air shower reconstruction
Objavljeno v RUNG: 04.10.2023; Ogledov: 353; Prenosov: 7
.pdf Celotno besedilo (5,81 MB)
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