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1.
Anthropic settlementsʹ impact on the light-absorbing aerosol concentrations and heating rate in the arctic
Niccolò Losi, Piotr Markuszewski, Martin Rigler, Asta Gregorič, Griša Močnik, Violetta Drozdowska, Przemek Makuch, Tymon Zielinski, Paulina Pakszys, Małgorzata Kitowska, 2023, izvirni znanstveni članek

Opis: Light-absorbing aerosols (LAA) impact the atmosphere by heating it. Their effect in the Arctic was investigated during two summer Arctic oceanographic campaigns (2018 and 2019) around the Svalbard Archipelago in order to unravel the differences between the Arctic background and the local anthropic settlements. Therefore, the LAA heating rate (HR) was experimentally determined. Both the chemical composition and high-resolution measurements highlighted substantial differences between the Arctic Ocean background (average eBC concentration of 11.7 ± 0.1 ng/m3) and the human settlements, among which the most impacting appeared to be Tromsø and Isfjorden (mean eBC of 99.4 ± 3.1 ng/m3). Consequently, the HR in Isfjorden (8.2 × 10−3 ± 0.3 × 10−3 K/day) was one order of magnitude higher than in the pristine background conditions (0.8 × 10−3 ± 0.9 × 10−5 K/day). Therefore, we conclude that the direct climate impact of local LAA sources on the Arctic atmosphere is not negligible and may rise in the future due to ice retreat and enhanced marine traffic.
Ključne besede: light-absorbing aerosols, black carbon, climate change, heating rate
Objavljeno v RUNG: 21.12.2023; Ogledov: 574; Prenosov: 5
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2.
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: 595; Prenosov: 6
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3.
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: 578; Prenosov: 6
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4.
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: 802; Prenosov: 7
.pdf Celotno besedilo (5,81 MB)
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5.
FOV direction and image size calibration of Fluorescence Detector using light source on UAV
A. Nakazawa, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: In the Telescope Array (TA) experiment, we have been observing cosmic rays using a Fluorescence Detector (FD). More than 10 years have passed since we started this observation, and the accuracy of the observation has become more important than ever. We have developed the "Opt-copter" as a calibration device for the FDs. The Opt-copter is an unmanned aerial vehicle (UAV) equipped with a light source and can fly freely within the FD's field of view (FOV). In addition, the Opt-copter is equipped with a high-precision RTK-GPS, which enables it to accurately determine the position of the light source in flight. With this device, we can obtain detailed information on the optical characteristics of the FD. So far, we have reported on the configuration of the device and the analysis of the FOV direction. In this presentation, we will report on the new FOV analysis and image size analysis.
Ključne besede: Telescope Array, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, light source, calibration, UAV, FOV
Objavljeno v RUNG: 04.10.2023; Ogledov: 832; Prenosov: 7
.pdf Celotno besedilo (7,14 MB)
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6.
Energy spectrum of cosmic rays measured using the Pierre Auger Observatory
V. Novotný, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci

Opis: We present the energy spectrum of cosmic rays measured at the Pierre Auger Observatory from 6×10^15 eV up to the most extreme energies where the accumulated exposure reaches about 80 000 km^2sr yr. The wide energy range is covered with five different measurements, namely using the events detected by the surface detector with zenith angles below 60 degrees and applying different reconstruction method also above 60 degrees, those collected by a denser array, the hybrid events simultaneously recorded by the surface and fluorescence detectors, and using those events in which the signal is dominated by Cherenkov light registered by the high-elevation telescopes. In this contribution, we report updates of the analysis techniques and present the spectrum obtained by combining the five different measurements. Spectral features occurring in the wide energy range covered by the Observatory are discussed.
Ključne besede: Pierre Auger Observatory, indirect detection, fluorescence detection, surface detection, hybrid detection, ultra-high energy, cosmic rays, cerenkov light, energy spectrum, inclined showers
Objavljeno v RUNG: 03.10.2023; Ogledov: 538; Prenosov: 5
.pdf Celotno besedilo (1,45 MB)
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7.
Study on multi-ELVES in the Pierre Auger Observatory
A. Vásquez Ramírez, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity.
Ključne besede: Pierre Auger Observatory, indirect detection, fluorescence detection, UV light, multi-ELVES, lightning
Objavljeno v RUNG: 03.10.2023; Ogledov: 681; Prenosov: 4
.pdf Celotno besedilo (1,25 MB)
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8.
Cosmic Ray Composition between 2 PeV and 2 EeV measured by the TALE Fluorescence Detector
T. AbuZayyad, Jon Paul Lundquist, 2022, 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 composition using TALE FD data collected over a period of ∼7 years. TALE FD data is used to measure the Xmax distributions of showers seen in the energy range of 10^15.3 - 10^18.3 eV. The data distributions are fit to Monte Carlo distributions of {H, He, N, Fe} cosmic-ray primaries for energies up to 10^18 eV. Mean Xmax values are measured for the full energy range. TALE observes a light composition at the "Knee", that gets gradually heavier as energy increases toward the "Second-Knee". An increase in the Xmax elongation rate is observed at energies just above 10^17.3 eV indicating a change in the cosmic rays composition from a heavier to a lighter mix of primaries.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, composition
Objavljeno v RUNG: 02.10.2023; Ogledov: 652; Prenosov: 5
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9.
Cosmic Ray Energy Spectrum measured by the TALE Fluorescence Detector
T. AbuZayyad, Jon Paul Lundquist, 2022, 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 using TALE FD data collected over a period of ∼7 years. The data set used for this measurement is the same one used for the mass composition measurement that is presented, as a separate contribution, at this conference. The energy spectrum shows features consistent with the "knee" and the "second knee"; a similar result to our previous energy spectrum publication. This time using a different hadronic model, and different event selection criteria as explained in the text of this proceeding.
Ključne besede: Telescope Array, TALE, low energy extension, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, energy spectrum
Objavljeno v RUNG: 02.10.2023; Ogledov: 514; Prenosov: 6
.pdf Celotno besedilo (2,92 MB)
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10.
Cosmic Ray Composition in the Second Knee Region as Measured by the TALE Hybrid Detector
R. Abbasi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Telescope Array Low-energy Extension (TALE) experiment is a hybrid air shower detector for the observation of air showers induced by cosmic rays with energy above 10^16 eV. 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 made up of 80 scintillation counters, including 40 with 400 m spacing and 40 with 600 m spacing. A triggering system for the TALE-SD using an external trigger from the TALE-FD, a so-called hybrid trigger, allows for a lower energy threshold. The TALE hybrid trigger system has been working since 2018. Here we present an estimate of the performance of hybrid detection using a Monte Carlo simulation, and a first measurement of the cosmic ray composition and spectrum using the TALE-Hybrid detector.
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, composition
Objavljeno v RUNG: 02.10.2023; Ogledov: 637; Prenosov: 5
.pdf Celotno besedilo (2,41 MB)
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