21. Search for EeV photon-induced events at the Telescope ArrayI. Kharuk, R. U. Abbasi, Y. Abe, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, 2023, published scientific conference contribution Abstract: We report on the updated results on the search for photon-like-induced events in the data, collected by Telescope Array's Surface Detectors during the last 14 years. In order to search for photon-like-induced events, we trained a neural network on Monte-Carlo simulated data to distinguish between the proton-induced and photon-induced air showers. Both reconstructed composition-sensitive parameters and raw signals registered by the Surface Detectors are used as input data for the neural network. The classification threshold was optimized to provide the strongest possible constraint on the photons' flux.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, photons, neural network, machine learning
Published in RUNG: 09.10.2023; Views: 680; Downloads: 6
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22. Systematic uncertainty in the analysis of the TA fluorescence detector from fluorescence yield modelsKohei Komori, R. U. Abbasi, Y. Abe, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, 2023, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, TAx4, indirect detection, fluorescence detection, fluorescence yield, ultra-high energy, cosmic rays, energy uncertainty
Published in RUNG: 09.10.2023; Views: 631; Downloads: 5
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23. Monocular and hybrid analysis for TA×4 fluorescence detectorsYuki Kusumori, R. U. Abbasi, Y. Abe, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, 2023, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, TAx4, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, energy spectrum, composition
Published in RUNG: 09.10.2023; Views: 580; Downloads: 6
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24. Cosmic ray energy spectrum and mass composition with the TALE fluorescence detectorT. Abu-Zayyad, R. U. Abbasi, Y. Abe, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Douglas R. Bergman, S. A. Blake, Jon Paul Lundquist, 2023, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, TALE, low energy extension, indirect detection, hybrid detection
Published in RUNG: 09.10.2023; Views: 516; Downloads: 5
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25. A study of the systematic effects on the energy scale for the measurement of UHECR spectrum by the TA SD arrayKeitaro Fujita, R. U. Abbasi, Y. Abe, T. Abu-Zayyad, M. Allen, Yasuhiko Arai, R. Arimura, E. Barcikowski, J. W. Belz, Jon Paul Lundquist, 2023, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, surface detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, energy spectrum, fluorescence yield, missing energy, systematics
Published in RUNG: 09.10.2023; Views: 642; Downloads: 4
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26. Cosmic ray mass composition measurement with the TALE hybrid detectorK. Fujita, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, TALE, low energy extension, indirect detection, hybrid detection, ground array, infill array, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, composition
Published in RUNG: 09.10.2023; Views: 576; Downloads: 6
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27. Telescope Array Cloud Ranging TestT. Okuda, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, fluorescence detection, cerenkov light, ultra-high energy, cosmic rays, atmosphere, cloud detection, exposure, air shower reconstruction
Published in RUNG: 04.10.2023; Views: 799; Downloads: 7
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28. FOV direction and image size calibration of Fluorescence Detector using light source on UAVA. Nakazawa, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, fluorescence detection, ultra-high energy, cosmic rays, light source, calibration, UAV, FOV
Published in RUNG: 04.10.2023; Views: 827; Downloads: 7
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29. Current status and prospects of surface detector of the TAx4 experimentE. Kido, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. A surface detector (SD) array covers approximately 700 km^2, and the SD array is surrounded by three fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with energies greater than 57 EeV from the TA SD data. In order to confirm this evidence with more data, we started the TAx4 experiment which expands the detection area using new SDs and FDs. We started construction of new SDs which are arranged in a square grid with 2.08 km spacing at the north east and south east of the TA SD array. More than half of the new SDs are already deployed and running. We present the current status of the TAx4 SD, trigger efficiency and exposure prospects for the highest energy part of the cosmic ray spectrum.
Keywords: Telescope Array, TAx4, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, trigger efficiency
Published in RUNG: 04.10.2023; Views: 700; Downloads: 8
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30. A study of analysis method for the identification of UHECR source typeF. Yoshida, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: The autocorrelation analysis using the arrival direction of Ultra High Energy Cosmic Rays (UHECRs) has been previously reported by the Telescope Array (TA) experiment. It is expected that the autocorrelation function reflects the source distribution. We simulate the expected arrival direction distribution of the cosmic rays using the catalogs of candidate sources. We take into account random deflection in the magnetic fields, with the magnitude of deflection determined by the charge and energy of the cosmic rays, coherence length and magnitude of the extragalactic magnetic field (EGMF), and by distance to source. In addition, in order to compare with the results of TA experiment, we consider the TA exposure. We compare the autocorrelation of the arrival directions corresponding to different source catalogs with the isotropic distribution. We calculate the autocorrelation function for each type of source candidates using this procedure. We will discuss the ability of this method to identify the source type of UHECRs.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, energy spectrum, composition, anisotropy, autocorrelation, source models, magnetic fields
Published in RUNG: 04.10.2023; Views: 761; Downloads: 6
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