Toshihiro Fujii
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View article: Detection of ultra-high-energy cosmic rays in the southern hemisphere with FAST: data acquisition and preliminary results
Detection of ultra-high-energy cosmic rays in the southern hemisphere with FAST: data acquisition and preliminary results Open
Ultra-high-energy cosmic rays (UHECRs) remain one of the greatest mysteries in astroparticle physics. The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a next-generation cosmic ray experiment which utilizes ground-based …
View article: Progress towards stereo observation of ultra-high-energy cosmic rays with Fluorescence detector Array of Single-pixel Telescopes
Progress towards stereo observation of ultra-high-energy cosmic rays with Fluorescence detector Array of Single-pixel Telescopes Open
Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles ever detected. Cosmic rays that achieve the highest energies are rare, and their flux at Earth is extremely low. As a result, next-generation experiments with large ef…
View article: Tubulin and <scp>GTP</scp> Are Crucial Elements for Postsynaptic Density Construction and Aggregation
Tubulin and <span>GTP</span> Are Crucial Elements for Postsynaptic Density Construction and Aggregation Open
In our previous experiments on the postsynaptic density lattice (PSDL), which is thought to serve as the backbone structure for the PSD, we suggested that tubulin plays a fundamental role in the PSD structure at excitatory synapses. In thi…
View article: Latest updates and results from the Fluorescence detector Array of Single-pixel Telescopes (FAST)
Latest updates and results from the Fluorescence detector Array of Single-pixel Telescopes (FAST) Open
View article: Ultra-high-energy cosmic ray detection using next-generation prototypes of the Fluorescence detector Array of Single-pixel Telescopes (FAST) in both hemispheres
Ultra-high-energy cosmic ray detection using next-generation prototypes of the Fluorescence detector Array of Single-pixel Telescopes (FAST) in both hemispheres Open
Unraveling the origin and nature of ultra-high-energy cosmic rays (UHECRs) stands as an essential inquiry in astroparticle physics. Motivated by new observational capabilities, the Fluorescence detector Array of Single-pixel Telescopes (FA…
View article: Intermediate Fluence Downward Terrestrial Gamma Ray Flashes as Observed by the Telescope Array Surface Detector
Intermediate Fluence Downward Terrestrial Gamma Ray Flashes as Observed by the Telescope Array Surface Detector Open
On 11 September 2021, two small thunderstorms developed over the Telescope Array Surface Detector (TASD) that produced an unprecedented number of six downward terrestrial gamma ray flashes (TGFs) within one‐hour timeframe. The TGFs occurre…
View article: First Time-Resolved Leader Spectra associated with a Downward Terrestrial Gamma-Ray Flash detected at the Telescope Array Surface Detector
First Time-Resolved Leader Spectra associated with a Downward Terrestrial Gamma-Ray Flash detected at the Telescope Array Surface Detector Open
Optical emissions associated with Terrestrial Gamma-ray Flashes (TGFs) have recently become important subjects in space-based and ground-based observations since these emissions play crucial roles in understanding the generation of TGFs du…
View article: Observation of Declination Dependence in the Cosmic Ray Energy Spectrum
Observation of Declination Dependence in the Cosmic Ray Energy Spectrum Open
We report on an observation of the difference between northern and southern skies of the ultrahigh energy cosmic ray energy spectrum with a significance of ${\sim}8σ$. We use measurements from the two largest experiments$\unicode{x2014}$th…
View article: The past and future 20-years endeavor for discovering origins of ultra-high energy cosmic rays – Rapporteur’s summary of cosmic ray indirect –
The past and future 20-years endeavor for discovering origins of ultra-high energy cosmic rays – Rapporteur’s summary of cosmic ray indirect – Open
This article is the rapporteur's summary of the cosmic ray indirect sessions\nof the 38th International Cosmic Ray Conference in Nagoya, Japan. The\nrapporteur highlights cosmic ray indirect observatories around the world, and\nreviews a s…
View article: An extremely energetic cosmic ray observed by a surface detector array
An extremely energetic cosmic ray observed by a surface detector array Open
Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting area…
View article: Observing cosmic-ray extensive air showers with a silicon imaging detector
Observing cosmic-ray extensive air showers with a silicon imaging detector Open
Extensive air showers induced from high-energy cosmic rays provide a window into understanding the most energetic phenomena in the universe. We present a new method for observing these showers using the silicon imaging detector Subaru Hype…
View article: Data of an extremely energetic cosmic ray observed by a surface detector array of Telescope Array experiment
Data of an extremely energetic cosmic ray observed by a surface detector array of Telescope Array experiment Open
0 : raw data 1 : event display 2 : skymaps Shared by the Telescope Array Collaboration
View article: INTERACTION OF POLYMERIZING TUBULIN WITH POSTSYNAPTIC DENSITY
INTERACTION OF POLYMERIZING TUBULIN WITH POSTSYNAPTIC DENSITY Open
View article: Measurement of UHECR energy spectrum with the Pierre Auger Observatory and the Telescope Array
Measurement of UHECR energy spectrum with the Pierre Auger Observatory and the Telescope Array Open
The measurement of the energy spectrum of ultra-high-energy cosmic rays (UHECRs) is of crucial importance to clarify their origin, acceleration mechanisms, and propagation processes in inter-Galactic and Galactic space. The Pierre Auger Ob…
View article: EUSO-SPB1 mission and science
EUSO-SPB1 mission and science Open
View article: Detecting ultra-high-energy cosmic rays with prototypes of the Fluorescence detector Array of Single-pixel Telescopes (FAST) in both hemispheres
Detecting ultra-high-energy cosmic rays with prototypes of the Fluorescence detector Array of Single-pixel Telescopes (FAST) in both hemispheres Open
Ultra-high energy cosmic rays (UHECRs), whose energy are beyond $10^{18}~\\mathrm{eV}$, are the most energetic particles we have ever detected.\nThe latest results seem to indicate a heavier composition at the highest energies, complicatin…
View article: Auger@TA: An Auger-like surface detector micro-array embedded within the Telescope Array Project
Auger@TA: An Auger-like surface detector micro-array embedded within the Telescope Array Project Open
The Pierre Auger Observatory (Auger) and the Telescope Array Project (TA) are the two largest ultra-high-energy cosmic ray (UHECR) observatories in the world. One obstacle in pursuing full-sky UHECR physics is the apparent discrepancy in f…
View article: Influence of Galactic magnetic fields on UHECR energy spectrum and mass composition on the Earth
Influence of Galactic magnetic fields on UHECR energy spectrum and mass composition on the Earth Open
Considering source population, mass composition, and propagation in magnetic fields is important to reveal the origin of ultrahigh-energy cosmic rays (UHECRs). Currently, Telescope Array (TA) and Auger experiments have observed the energy …
View article: Science with the Global Cosmic-ray Observatory (GCOS)
Science with the Global Cosmic-ray Observatory (GCOS) Open
The Global Cosmic-ray Observatory (GCOS) is a proposed large-scale\nobservatory for studying ultra-high-energy cosmic particles, including\nultra-high-energy cosmic rays (UHECRs), photons, and neutrinos. Its primary\ngoal is to characteris…
View article: “Ultra-High-Energy Cosmic-Rays (UHECR): at the Intersection of the Cosmic and Energy Frontiers” -- Overview of the Snowmass UHECR white paper and roadmap
“Ultra-High-Energy Cosmic-Rays (UHECR): at the Intersection of the Cosmic and Energy Frontiers” -- Overview of the Snowmass UHECR white paper and roadmap Open
As part of the US "Snowmass" community planning exercise, the UHECR community has come together to write a comprehensive white paper discussing the recent progress and open questions of the field, as they relate to the overarching goals of…
View article: Cosmic-ray and gamma-ray constraints on very-heavy dark matter decay
Cosmic-ray and gamma-ray constraints on very-heavy dark matter decay Open
Decaying very-heavy dark matter (VHDM) particles at energies $\\gtrsim 10^9$ GeV can contribute to the ultrahigh-energy cosmic ray spectrum. However, the composition measurements by Pierre Auger Observatory indicate the presence of heavy-n…
View article: Reconstruction procedure of the Fluorescence detector Array of Single-pixel Telescopes
Reconstruction procedure of the Fluorescence detector Array of Single-pixel Telescopes Open
The Fluorescence detector Array of Single-pixel Telescopes (FAST) is one of several proposed designs for a next-generation cosmic-ray detector. Such detectors will require enormous collecting areas whilst also needing to remain cost-effici…
View article: First High‐Speed Video Camera Observations of a Lightning Flash Associated With a Downward Terrestrial Gamma‐Ray Flash
First High‐Speed Video Camera Observations of a Lightning Flash Associated With a Downward Terrestrial Gamma‐Ray Flash Open
In this paper, we present the first high‐speed video observation of a cloud‐to‐ground lightning flash and its associated downward‐directed Terrestrial Gamma‐ray Flash (TGF). The optical emission of the event was observed by a high‐speed vi…
View article: ISAI: Investigating Solar Axion by Iron-57
ISAI: Investigating Solar Axion by Iron-57 Open
The existence of the axion is a unique solution for the strong CP problem, and the axion is one of the most promising candidates of the dark matter. Investigating Solar Axion by Iron-57 (ISAI) is being prepared as a complemented table-top …
View article: Effects of the Galactic Magnetic Field on the UHECR Correlation Studies with Starburst Galaxies
Effects of the Galactic Magnetic Field on the UHECR Correlation Studies with Starburst Galaxies Open
We estimate the biases caused by the coherent deflection of cosmic rays due to the Galactic magnetic field (GMF) in maximum likelihood analyses for searches of ultrahigh-energy cosmic-ray sources in the literature. We simulate mock event d…
View article: Revisiting ultrahigh-energy constraints on decaying super-heavy dark matter
Revisiting ultrahigh-energy constraints on decaying super-heavy dark matter Open
We revisit constraints on decaying very heavy dark matter (VHDM) using the latest ultrahigh-energy cosmic-ray (UHECR; $E\gtrsim 10^{18}$ eV) data and ultrahigh-energy (UHE) $γ$-ray flux upper limits, measured by the Pierre Auger Observator…
View article: Ultra high energy cosmic rays The intersection of the Cosmic and Energy Frontiers
Ultra high energy cosmic rays The intersection of the Cosmic and Energy Frontiers Open
View article: Estimation and reduction of the biases by the galactic magnetic field on the UHECR correlation studies
Estimation and reduction of the biases by the galactic magnetic field on the UHECR correlation studies Open
The correlation studies between ultrahigh-energy cosmic ray (UHECR) anisotropy and source candidates are keys to understand the origin of UHECRs. Especially, studies with consideration of source models, magnetic fields, and mass compositio…
View article: Search for the large-scale cosmic-ray anisotropies using the TA and TALE surface detector arrays
Search for the large-scale cosmic-ray anisotropies using the TA and TALE surface detector arrays Open
Origins of ultra-high-energy cosmic rays (UHECRs) are still largely unknown. In particular, the “2nd knee” around 10 17 eV could be related to a transition of origins from the galactic to extra-galactic sources. In this scenario, one would…
View article: The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and the Telescope Array
The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and the Telescope Array Open
In the study of cosmic rays, the measurement of the energy spectrum of the primaries is one of the main issues and provides fundamental information on the most energetic phenomena in the Universe. At ultrahigh energies, beyond 10 18 eV, th…