arXiv subjects

Yoshiki Tsunesada

Publications and source records attributed to Yoshiki Tsunesada.

12 recordsLinked to original sources

arXiv2025

Updated comparison of the UHECR energy spectra measured by the Pierre Auger Observatory and the Telescope Array

The Pierre Auger and Telescope Array joint Working Group on the UHECR energy spectrum was established in 2012 to analyze energy scale uncertainties in both experiments and to in vestigate their systematic differences, particularly in the spectral shape of the flux measurements. Previous studies have indeed shown that, within systematic uncertainties, the energy s pectra measured by the two observatories are consistent below~$10\,\mathrm{EeV}$. However, at higher energies, a significant difference remains. In this work, we re-examine this discrepan cy in greater detail and explore its possible origins. We consider systematic and statistical uncertainties, including the conversion from directly measured observables to energy and the calculation of exposures. We present an updated energy scale comparison between the two experiments and updated flux measurements in the common declination band.

astro-ph.HE↗

arXiv2024

Comments concerning the paper "On the calibration of ultra-high energy EASs at the Yakutsk array and Telescope Array" by A.V.Glushkov et. al

In a recent review of a paper by the Yakutsk Group, submitted to the Journal Physics of Atomic Nuclei and arXiv, the energy scales of the Yakutsk and Telescope Array (TA) experiments were examined. The authors developed a custom detector response simulator incorporating ionization, bremsstrahlung, pair production, and Compton scattering. Applying this simulator to both Yakutsk and TA surface detectors, they concluded that the TA energy scale might be incorrect due to a misdefined ``response unit.'' They referenced the TA's ``energy deposit formula'' from the literature, scaling it by two factors attributed to the thickness and density of the TA scintillator. Their simulations, using the QGSJET-II-04 hadronic interaction model, agreed with TA's calculations for vertical showers but not for inclined showers, suggesting an incorrect VEM unit of 2.05 MeV. However, this conclusion was found to be incorrect. The TA's energy deposit formula, derived from detailed Monte Carlo simulations using GEANT4, accurately represents the most probable energy deposit by a charged particle in the TA scintillator. The value of 2.05 MeV accounts for the scintillator's thickness and density and is validated by excellent agreement between TA's simulated and observed data. The Yakutsk Group's misinterpretation and incorrect application of the TA formula led to their erroneous conclusion.

astro-ph.HE↗

arXiv2019

Depth of maximum of air-shower profiles: testing the compatibility of measurements performed at the Pierre Auger Observatory and the Telescope Array experiment

At the Pierre Auger Observatory and the Telescope Array, the measurements of depths of maximum of air-shower profiles, $X_\mathrm{max}$, are performed using direct observations of the longitudinal development of showers with the help of the fluorescence telescopes. Though the same detection technique is used at both installations, the straightforward comparison of the characteristics of the measured $X_\mathrm{max}$ distributions is not possible due to the different approaches to the analysis of the recorded events. In this work, the Auger-Telescope Array composition working group presents a technique to compare the $X_\mathrm{max}$ measurements from the Auger Observatory and the Telescope Array. Applying this technique the compatibility of the first two moments of the measured $X_\mathrm{max}$ distributions is qualitatively tested for energies $10^{18.2}~{\rm eV} < E < 10^{19.0}~{\rm eV}$ using the recently published Telescope Array data from the Black Rock Mesa and Long Ridge fluorescence detector stations. For a quantitative comparison, simulations of air showers with EPOS-LHC, folded with effects of the Telescope Array detector, are required along with the inclusion in the analysis of the systematic uncertainties in the measurements of $X_\mathrm{max}$ and the energies of the events.

astro-ph.HE↗

arXiv2017

Measurement of Energy Spectrum of Ultra-High Energy Cosmic Rays

Ultra-High Energy Cosmic Rays (UHECRs) are charged particles of energies above $10^{18}$ eV that originate outside of the Galaxy. Because the flux of the UHECRs at Earth is very small, the only practical way of observing UHECRs is by measuring the extensive air showers (EAS) produced by UHECRs in the atmosphere. This is done by using air fluorescence detectors and giant arrays of particle detectors on the ground. The Pierre Auger Observatory (Auger) and Telescope Array (TA) are two large cosmic ray experiments which use such techniques and cover 3000 km$^2$ and 700 km$^2$ areas on the ground, respectively. In this paper, we present the UHECR spectrum reported by the TA, using an exposure of 6300 km$^2$ sr yr accumulated over 7 years of data taking, and the corresponding result of Auger, using 10 years of data with a total exposure exceeding 50000 km$^2$ sr yr. We review the astrophysical interpretation of the two measurements, and discuss their systematic uncertainties.

astro-ph.HE↗

arXiv2013

Mass Composition Working Group Report at UHECR-2012

We present a summary of the measurements of mass sensitive parameters at the highest cosmic ray energies done by several experiments. The Xmax distribution as a function of energy has been measured with fluorescence telescopes by the HiRes, TA and Auger experiments and with Cherenkov light detectors by Yakutsk. The or the average mass ( ) has been also inferred using ground detectors, such as muon and water Cherenkov detectors. We discuss the different data analyses elaborated by each collaboration in order to extract the relevant information. Special attention is given to the different approaches used in the analysis of the data measured by fluorescence detectors in order to take into account detector biases. We present a careful analysis of the stability and performance of each analysis. The results of the different experiments will be compared and the discrepancies or agreements will be quantified.

astro-ph.HE↗

arXiv2012

Calibration of Photomultiplier Tubes for the Fluorescence Detector of Telescope Array Experiment using a Rayleigh Scattered Laser Beam

We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.

astro-ph.IM↗

arXiv2011

Highlights from Telescope Array

The results from the first three years observation in Telescope Array are reviewed. The energy spectrum, mass composition, and anisotropy in arrival directions of ultra-high energy cosmic rays are discussed. The energy spectrum of cosmic rays with energies above $10^{18}$ eV is determined using the data of the fluorescence detectors, surface detectors, and with a hybrid shower reconstruction technique using the both data. The ankle structure is clearly found at $10^{18.7}$ eV. The second bending point is also identified, at which the flux of cosmic rays begins to decrease and the spectral index changes from $E^{-2.68}$ to $E^{-4.2}$. The study of shower development using the fluorescence detector data shows that proton is dominant in cosmic rays above $10^{18.2}$ eV. No apparent anisotropies in the arrival direction of cosmic rays are found. I also present further experimental extensions which are being developed at the Telescope Array site.

astro-ph.HE↗

arXiv2011

The atmospheric transparency measured with a LIDAR system at the Telescope Array experiment

An atmospheric transparency was measured using a LIDAR with a pulsed UV laser (355nm) at the observation site of Telescope Array in Utah, USA. The measurement at night for two years in $2007\sim 2009$ revealed that the extinction coefficient by aerosol at the ground level is $0.033^{+0.016}_{-0.012} \rm km^{-1}$ and the vertical aerosol optical depth at 5km above the ground is $0.035^{+0.019}_{-0.013}$. A model of the altitudinal aerosol distribution was built based on these measurements for the analysis of atmospheric attenuation of the fluorescence light generated by ultra high energy cosmic rays.

astro-ph.IM↗

arXiv2008

Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors

We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100-times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

gr-qc↗

arXiv2004

Plans for the LIGO-TAMA Joint Search for Gravitational Wave Bursts

We describe the plans for a joint search for unmodelled gravitational wave bursts being carried out by the LIGO and TAMA collaborations using data collected during February-April 2003. We take a conservative approach to detection, requiring candidate gravitational wave bursts to be seen in coincidence by all four interferometers. We focus on some of the complications of performing this coincidence analysis, in particular the effects of the different alignments and noise spectra of the interferometers.

gr-qc↗

arXiv2004

Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses

We present data-analysis schemes and results of observations with the TAMA300 gravitational-wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp-wave analysis, because precise waveform templates are not available. We used an excess-power filter for the extraction of gravitational-wave candidates, and developed two methods for the reduction of fake events caused by non-stationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. The resultant event candidates were interpreted from an astronomical viewpoint. We set an upper limit of 2.2x10^3 events/sec on the burst gravitational-wave event rate in our Galaxy with a confidence level of 90%. This work sets a milestone and prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector.

gr-qc↗

arXiv2004

On Detection of Black Hole Quasi-Normal Ringdowns: Detection Efficiency and Waveform Parameter Determination in Matched Filtering

Gravitational radiation from a slightly distorted black hole with ringdown waveform is well understood in general relativity. It provides a probe for direct observation of black holes and determination of their physical parameters, masses and angular momenta (Kerr parameters). For ringdown searches using data of gravitational wave detectors, matched filtering technique is useful. In this paper, we describe studies on problems in matched filtering analysis in realistic gravitational wave searches using observational data. Above all, we focus on template constructions, matches or signal-to-noise ratios (SNRs), detection probabilities for Galactic events, and accuracies in evaluation of waveform parameters or black hole hairs. We have performed matched filtering analysis for artificial ringdown signals which are generated with Monte-Carlo technique and injected into the TAMA300 observational data. It is shown that with TAMA300 sensitivity, the detection probability for Galactic ringdown events is about 50% for black holes of masses greater than $20 M_{\odot}$ with SNR $> 10$. The accuracies in waveform parameter estimations are found to be consistent with the template spacings, and resolutions for black hole masses and the Kerr parameters are evaluated as a few % and $\sim 40 %$, respectively. They can be improved up to $< 0.9 %$ and $< 24 %$ for events of ${\rm SNR} \ge 10$ by using fine-meshed template bank in the hierarchical search strategy.

gr-qc↗