31. 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: 1089; Downloads: 7
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32. 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: 1047; Downloads: 7
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33. 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: 921; Downloads: 8
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34. 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: 997; Downloads: 8
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35. Telescope Array Surface Detector Energy and Arrival Direction Estimation Using Deep LearningO. Kalashev, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: A novel ultra-high-energy cosmic rays energy and arrival direction reconstruction method for Telescope Array surface detector is presented. The analysis is based on a deep convolutional neural network using detector signal time series as the input and the network is trained on a large Monte-Carlo dataset. This method is compared in terms of statistical and systematic energy and arrival direction determination errors with the standard Telescope Array surface detector event reconstruction procedure.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, energy, arrival directions, reconstruction, machine learning, neural network
Published in RUNG: 04.10.2023; Views: 810; Downloads: 6
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36. The status of the TALE surface detector array and TALE infill projectA. Iwasakia, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: Routine hybrid observations of the surface detectors (SD) in conjunction with the fluorescence detectors (FD) of the Telescope Array Low-energy Extension (TALE) began in November 2018. In this presentation, we will describe the simulation studies of detector aperture and resolution of the TALE SD, and report on the latest observation results other than the energy spectrum. We are also in the process of expanding the experiment by 50 SDs, with even smaller nearest-neighbor spacing, in order lower the energy threshold to match that of the Cherenkov-dominated events seen by the FD. Details of the upgrade and expected performance of this new extension will be discussed.
Keywords: Telescope Array, TALE, low energy extension, indirect detection, surface detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays
Published in RUNG: 04.10.2023; Views: 849; Downloads: 81
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37. Update on the large-scale cosmic-ray anisotropy search at the highest energies by the Telescope Array ExperimentT. Fujii, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, anisotropy, large-scale, dipole
Published in RUNG: 04.10.2023; Views: 856; Downloads: 4
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38. UHECR mass composition from anisotropy of their arrival directions with the Telescope Array SDM. Kuznetsov, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, composition, anisotropy, magnetic fields, 2MRS
Published in RUNG: 04.10.2023; Views: 831; Downloads: 5
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39. 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, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, hybrid detection, ground array, fluorescence detection, ultra-high energy, cosmic rays, Xmax, proton-air cross-section, high energy particle interaction
Published in RUNG: 04.10.2023; Views: 910; Downloads: 4
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40. Observation of Variations in Cosmic Ray Shower Rates During Thunderstorms and Implications for Large-Scale Electric Field ChangesR. Abbasi, Jon Paul Lundquist, 2022, published scientific conference contribution Abstract: 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.
Keywords: Telescope Array, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, shower profile, lightning, atmospheric electric fields
Published in RUNG: 04.10.2023; Views: 732; Downloads: 5
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