A5041375615- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Bone health and osteoporosis research
- Radio Astronomy Observations and Technology
- Collagen: Extraction and Characterization
- Ultrasonics and Acoustic Wave Propagation
- Particle physics theoretical and experimental studies
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Nuclear Physics and Applications
- Sensor Technology and Measurement Systems
- Bone Tissue Engineering Materials
- Tendon Structure and Treatment
- Particle Accelerators and Free-Electron Lasers
- Drilling and Well Engineering
- Stellar, planetary, and galactic studies
- Dental Radiography and Imaging
- Atmospheric Ozone and Climate
Kyoto University
2012-2024
Kavli Institute for the Physics and Mathematics of the Universe
2020-2024
The University of Tokyo
2020-2024
Chonnam National University
2023-2024
Chonnam National University Hospital
2024
Japan Aerospace Exploration Agency
2014-2018
Institute of Space and Astronautical Science
2014-2018
RIKEN
2013-2018
Université Savoie Mont Blanc
2013-2014
Stanford University
1999-2013
The gamma-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with interstellar gas and radiation fields Milky Way. Observations these provide a tool to study cosmic-ray origin propagation, medium. We present measurements first 21 months Fermi-LAT mission compare models emission generated using GALPROP code. are fitted data incorporate astrophysical input for distribution sources, fields. To assess uncertainties associated input, grid created varying...
A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by Large Area Telescope on board Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 lasted approximately 16 days. second was September 2010 4 During these outbursts, flux nebula increased factors of four six, respectively. brevity implies that gamma rays were emitted via...
We report on the gamma-ray activity of high-synchrotron-peaked BL Lacertae object Mrk 421 during first 1.5 years Fermi operation, from 2008 August 5 to 2010 March 12. find that Large Area Telescope (LAT) spectrum above 0.3 GeV can be well-described by a power-law function with photon index Gamma=1.78 +/- 0.02 and average flux F(>0.3 GeV)=(7.23 0.16) x 10^{-8} ph cm^{-2} s^{-1}. Over this time period, Fermi-LAT was evaluated 7-day-long intervals, showing significant variations in (up factor...
The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little escape from the shock and evolution through turbulent medium surrounding massive stars. Gamma can probe spreading ambient gas radiation fields. Fermi Large Area Telescope (LAT) has observed star-forming region Cygnus X. 1- 100-gigaelectronvolt images reveal 50-parsec-wide cocoon freshly accelerated that flood cavities carved stellar winds...
In three years of observations since the beginning nominal science operations in August 2008, Large Area Telescope (LAT) on board Fermi Gamma Ray Space has observed high-energy (>20 MeV) \gamma-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 ~ 20 MeV. The first Fermi-LAT catalog is a compilation these detections provides systematic study for time. To generate catalog, we examined 733 by Gamma-Ray Burst Monitor (GBM) processed each...
We present observations of the young supernova remnant (SNR) RX J1713.7−3946 with Fermi Large Area Telescope (LAT). clearly detect a source positionally coincident SNR. The is extended best-fit extension 055 ± 004 matching size non-thermal X-ray and TeV gamma-ray emission from remnant. positional coincidence allow us to identify LAT SNR J1713.7−3946. spectrum can be described by very hard power law photon index Γ = 1.5 0.1 that coincides in normalization steeper H.E.S.S.-detected at higher...
Abstract We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on Fermi Gamma-ray Space Telescope. Another 33 millisecond (MSPs) discovered deep radio searches of LAT sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems colocated with also harbor gamma-ray MSPs. This catalog thus reports roughly 340 and candidates, 10% all known pulsars, compared to ≤11 before Fermi. Half...
An analysis of solar neutrino data from the fourth phase Super-Kamiokande (SK-IV) October 2008 to May 2018 is performed and results are presented. The observation time dataset SK-IV corresponds 2970 days total live for all four phases 5805 days. For more precise measurements, several improvements applied in this analysis: lowering acquisition threshold 2015, further reduction spallation background using neutron clustering events, energy reconstruction considering variation PMT gain. observed...
We report on gamma-ray observations of the Crab Pulsar and Nebula using 8 months survey data with Fermi Large Area Telescope (LAT). The high quality light curve obtained ephemeris provided by Nancay Jodrell Bank radio telescopes shows two main peaks stable in phase energy. first peak leads pulse (281 \pm 12 21) mus, giving new constraints production site non-thermal emission pulsar magnetospheres. improved sensitivity unprecedented statistics afforded LAT enable precise measurement spectral...
We report observation of the supernova remnant IC443 (G189.1+3.0) with Fermi Gamma-ray Space Telescope Large Area (LAT) in energy band between 200MeV and 50GeV. is a shell-type mixed morphology located off outer Galactic plane where high-energy emission has been detected X-ray, GeV TeV gamma-ray bands. Past observations suggest interacting surrounding interstellar matter. Proximity dense shocked molecular clouds GeV-TeV regions by EGRET, MAGIC VERITAS suggests an interpretation that...
We report on the gamma-ray activity of blazar Mrk 501 during first 480 days Fermi operation. find that average LAT spectrum can be well described by a single power-law function with photon index 1.78 +/- 0.03. While we observe relatively mild flux variations Fermi-LAT (within less than factor 2), detect remarkable spectral variability where hardest observed within energy range is 1.52 0.14, and softest one 2.51 0.20. These unexpected changes do not correlate measured above 0.3GeV. In this...
We report on the observation of bright, long gamma-ray burst, GRB 090926A, by Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) instruments board \Fermi\ Space Telescope. 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in light curve that is present all detectors see this turn suggests there common region emission across entire energy range. addition, while separate high-energy power-law component has already been...
Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from companion star. Current physical models posit that shocked expanding gas the nova shell can produce X-ray emission but at higher energies has not been widely expected. Here, we report Fermi Large Area Telescope detection of variable gamma-ray (0.1-10 GeV) recently-detected optical symbiotic star V407 Cygni. We propose material interacts with dense ambient medium red giant primary, and particles be...
This is the first of a series papers aimed at characterizing populations detected in high-latitude sky Fermi-LAT survey. In this work, we focus on intrinsic spectral and flux properties source sample. We show that when selection effects are properly taken into account, Fermi sources average steeper than previously found (e.g., bright list) with an photon index 2.40 ± 0.02 over entire 0.1–100 GeV energy band. confirm flat spectrum radio quasars have spectra BL Lacertae objects 2.48 versus...
The flat-spectrum radio quasar 3C 454.3 underwent an extraordinary 5-day gamma-ray outburst in November 2010 where the daily flux measured with Fermi Large Area Telescope (LAT) at photon energies E>100 MeV reached (66+/-2) x 10^-6 ph cm^-2 s^-1. This is a factor of 3 higher than its previous maximum recorded December 2009 and ~5 times brighter Vela pulsar, which normally brightest source sky. 3-hr peak was (85+/-5) s^-1, corresponding to apparent isotropic luminosity 2.1+/-0.2 10^50 erg...
We present detailed analysis of two gamma-ray sources, 1FGL J1801.3−2322c and J1800.5−2359c, that have been found toward the supernova remnant (SNR) W28 with Large Area Telescope (LAT) on board Fermi Gamma-ray Space Telescope. is to be an extended source within boundary SNR W28, extensively overlap TeV HESS J1801−233, which associated a dense molecular cloud interacting SNR. The spectrum measured LAT from 0.2 100 GeV can described by broken power-law function break at ∼1 photon indices 2.09...
Nearby clusters and groups of galaxies are potentially bright sources high-energy gamma-ray emission resulting from the pair-annihilation dark matter particles. However, no significant has been detected so far in first 11 months observations with Fermi Large Area Telescope. We interpret this non-detection terms constraints on particle properties. In particular for leptonic annihilation final states masses greater than ~200 GeV, inverse Compton scattering CMB photons is expected to dominate...
We report on the discovery of \geq 100 MeV {\gamma} rays from binary system PSR B1259-63/LS 2883 using Large Area Telescope (LAT) board Fermi. The comprises a radio pulsar in orbit around Be star. LAT observations near apastron to ~ 60 days after time periastron, tp, 2010 December 15. No {\gamma}-ray emission was detected this source when it far periastron. Faint appeared as approached At tp + 30d, flux increased over period few peak 20-30 times that seen during pre-periastron period, but...
This is the first report of Fermi Gamma-Ray Space Telescope observations quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from Large Area Telescope, covering 2008 July 7–October 6, indicate strong, highly variable γ-ray emission with an average flux ∼3 × 10−6 photons cm−2 s−1, for energies >100 MeV. variable, distinct, symmetrically shaped flares increases by a factor several on timescale about 3 days. variability indicates compact region, and...
Analysis is presented for 15 months of data taken with the Large Area Telescope (LAT) on Fermi Gamma-ray Space 11 non-blazar active galactic nuclei (AGNs), including seven FRI radio galaxies and four FRII sources consisting two steep spectrum quasars. The broad line galaxy 3C 120 reported here as a γ-ray source first time. analysis based directional associations LAT in 3CR, 3CRR, MS4 (collectively referred to 3C-MS) catalogs. Seven eleven associated 3C-MS have spectral indices larger than...
Context. Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters high-energy gamma-ray emission. The observation this emission provides a powerful tool assess the pulsar population cluster, is essential for understanding importance binary systems evolution globular clusters, and complementary insights into magnetospheric processes.
The flat spectrum radio quasar 3C~454.3 underwent an extraordinary outburst in December 2009 when it became the brightest gamma-ray source sky for over one week. Its daily flux measured with Fermi Large Area Telescope at photon energies E>100 MeV reached F = 22+/-1 x 10^-6 ph cm^-2 s^-1, representing highest of any blazar ever recorded high-energy gamma-rays. It again 2010 April, triggering a pointed-mode observation by Fermi. correlated temporal and spectral properties during these...