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21.
Telescope Array Hot/Coldspot Study – Intermediate Scale Anisotropy
J. P. Lundquist, published scientific conference contribution abstract

Abstract: Indications of energy dependent intermediate scale anisotropy has been found in the arrival directions of ultra high energy cosmic rays with energies above 20 EeV in the northern hemisphere, using 7 years of TA surface detector data. The previously reported “hotspot‘” excess for E>57 EeV is found to correspond to a deficit, or “coldspot ”, of events for energies 2057 EeV has a Li Ma statistical significance of 4.62σ, and the deficit for energies 20Found in: ključnih besedah
Summary of found: ...Indications of energy dependent intermediate scale anisotropy has been found... ...cosmic rays, energy spectrum, anisotropy, magnetic deflection...
Keywords: cosmic rays, energy spectrum, anisotropy, magnetic deflection
Published: 28.04.2020; Views: 419; Downloads: 0
.pdf Fulltext (2,25 MB)

22.
Evidence of Intermediate-Scale Energy Spectrum Anisotropy of Cosmic Rays E>10^19.2 eV with the Telescope Array Surface Detector
J. P. Lundquist, published scientific conference contribution abstract

Abstract: Evidence of an intermediate-scale energy spectrum anisotropy has been found in the arrival directions of ultra-high energy cosmic rays of energies above 10^19.2 eV in the northern hemisphere, using 7 years of Telescope Array (TA) surface detector (SD) data. A relative energy distribution test is done comparing events inside oversampled spherical caps of equal exposure, to those outside, using the Poisson likelihood ratio. The center of maximum significance is at 139 R.A., 45 Dec., and has a deficit of events with energies 10^19.210^19.75 eV. The post-trial probability of this energy anisotropy, appearing by chance anywhere on an isotropic sky, is found by Monte Carlo (MC) simulation to be 9x10^-5 (3.74 σ_global).
Found in: ključnih besedah
Keywords: UHECR, cosmic rays, energy spectrum, anisotropy
Published: 29.04.2020; Views: 383; Downloads: 20
.pdf Fulltext (408,40 KB)

23.
A systematic uncertainty on the energy scale of the Telescope Array fluorescence detectors
J. P. Lundquist, T. Fujii, 2018, published scientific conference contribution

Abstract: The Telescope Array experiment (TA) is the largest cosmic-ray detector in the northern hemi-sphere and consists of a surface detector (SD) array, plus three fluorescence detector (FD) stations overlooking the SD. The large field-of-view of an FD allows for reconstruction of the air-shower development in the atmosphere by imaging ultra-violet fluorescence light from atmospheric nitrogen excited by UHECRs. In estimation of the primary energy it is necessary to add to the calorimetric energy observed by the FD a “missing energy”, meaning the fraction of the primary energy that is not deposited by charged particles in the air. We report on the measurement of the missing energy from observed data collected by the TA FD and TA SD, independently of Monte Carlo simulations, using a technique pioneered by the Pierre Auger Observatory. We also address the effect on the energy scale attributed to fluorescence yield parameters.
Found in: ključnih besedah
Keywords: UHECR, cosmic rays, energy spectrum
Published: 29.04.2020; Views: 354; Downloads: 18
.pdf Fulltext (4,74 MB)

24.
Energy-position correlation anisotropy of ultra-high energy cosmic rays with Telescope Array Data
J. P. Lundquist, published scientific conference contribution abstract

Abstract: Indication of an energy dependent intermediate-scale anisotropy has been found in the arrival directions of ultra-high energy cosmic rays with energies above 20 EeV in the northern hemisphere, using 7 years of TA surface detector data. The previously reported “hotspot“ excess for E>57 EeV is found to correspond to a deficit, or “coldspot“, of events for energies 2057 EeV has a Li-Ma statistical significance of 4.62σ, and the deficit for energies 20Found in: ključnih besedah
Summary of found: ...UHECR, energy spectrum, anisotropy, magnetic deflection...
Keywords: UHECR, energy spectrum, anisotropy, magnetic deflection
Published: 29.04.2020; Views: 389; Downloads: 0
.pdf Fulltext (1,84 MB)

25.
The Cosmic Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode
J. P. Lundquist, R.U. Abbasi, 2018, original scientific article

Abstract: We report on a measurement of the cosmic ray energy spectrum by the Telescope Array Low-Energy Extension (TALE) air fluorescence detector (FD). The TALE air FD is also sensitive to the Cherenkov light produced by shower particles. Low-energy cosmic rays, in the PeV energy range, are detectable by TALE as Cherenkov events. Using these events, we measure the energy spectrum from a low energy of ~2 PeV to an energy greater than 100 PeV. Above 100 PeV, TALE can detect cosmic rays using air fluorescence. This allows for the extension of the measurement to energies greater than a few EeV. In this paper, we describe the detector, explain the technique, and present results from a measurement of the spectrum using ~1000 hr of observation. The observed spectrum shows a clear steepening near 10^17.1 eV, along with an ankle-like structure at 10^16.2 eV. These features present important constraints on the origin of galactic cosmic rays and on propagation models. The feature at 10^17.1 eV may also mark the end of the galactic cosmic ray flux and the start of the transition to extragalactic sources.
Found in: ključnih besedah
Keywords: astroparticle physics, cosmic rays, UHECR, energy spectrum
Published: 30.04.2020; Views: 433; Downloads: 0
.pdf Fulltext (4,40 MB)

26.
Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique
J. P. Lundquist, T. Abu-Zayyad, 2015, original scientific article

Abstract: We measure the spectrum of cosmic rays with energies greater than eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.
Found in: ključnih besedah
Keywords: Ultra-high energy cosmic rays, Telescope Array, Hybrid spectrum
Published: 30.04.2020; Views: 502; Downloads: 0
.pdf Fulltext (267,06 KB)

27.
The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular mode
J. P. Lundquist, T. Abu-Zayyad, 2013, original scientific article

Abstract: We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array’s third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array’s middle drum detector and the direct comparison to the high resolution fly’s eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.
Found in: ključnih besedah
Keywords: UHECR, Energy spectrum, Fluorescence, Monocular
Published: 19.05.2020; Views: 320; Downloads: 0
.pdf Fulltext (926,83 KB)

28.
Measurement of the cosmic ray flux near the second knee with the Pierre Auger Observatory
Lukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Alan Coleman, 2019, published scientific conference contribution

Found in: ključnih besedah
Summary of found: ...ultra-high energy cosmic rays (UHECR), UHECR energy spectrum, second...
Keywords: ultra-high energy cosmic rays (UHECR), UHECR energy spectrum, second knee, Pierre Auger Observatory
Published: 16.06.2020; Views: 317; Downloads: 17
.pdf Fulltext (557,92 KB)

29.
Measurement of the spectrum of cosmic rays above 10^16.5 eV with Cherenkov–dominated events at the Pierre Auger Observatory
Lukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Vladimír Novotný, 2019, published scientific conference contribution

Found in: ključnih besedah
Summary of found: ...ultra-high energy cosmic rays (UHECRs), Pierre Auger Observatory, UHECR...
Keywords: ultra-high energy cosmic rays (UHECRs), Pierre Auger Observatory, UHECR energy spectrum, Cherenkov–dominated UHECR events
Published: 24.07.2020; Views: 314; Downloads: 13
.pdf Fulltext (377,09 KB)

30.
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