A5034589176- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Astronomy and Astrophysical Research
- Atomic and Subatomic Physics Research
- Astro and Planetary Science
- Radiation Detection and Scintillator Technologies
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- Stellar, planetary, and galactic studies
- Calibration and Measurement Techniques
- Seismology and Earthquake Studies
RIKEN
2020-2024
Kanagawa University
2022-2024
Osaka University
2024
Washington University in St. Louis
2024
Nippon Soken (Japan)
2021-2023
Rikkyo University
2016-2023
Kanazawa University
2023
Compact Imaging (United States)
2023
Université Paris-Saclay
2021
Institut de Recherche sur les Lois Fondamentales de l'Univers
2021
Abstract A recent report on the detection of very-high-energy gamma rays from V4641 Sagittarii (V4641 Sgr) up to ≈0.8 PeV has made it second confirmed “PeVatron” microquasar. Here we observation Sgr with X-Ray Imaging and Spectroscopy Mission (XRISM) in 2024 September. Thanks large field view low background, CCD imager Xtend successfully detected for first time X-ray extended emission around a significance ≳4.5 σ >10 based our imaging spectral analysis, respectively. The spatial extent is...
Abstract We report a new CO observation survey of LHAASO J0341+5258, using the Nobeyama Radio Observatory 45-m telescope. J0341+5258 is one unidentified ultra-high-energy (UHE; E > 100 TeV) gamma-ray sources detected by LHAASO. Our observations were conducted in 2024 February and March, with total time 36 hr, covering source (∼0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover> <mml:mrow> <mml:mo>.</mml:mo> </mml:mrow> <mml:mtext>°</mml:mtext>...
Abstract The astronomical origins of the most energetic galactic cosmic rays and gamma are still uncertain. X-ray follow-up candidate “PeVatrons”—systems producing with energies exceeding 1 PeV—can constrain their spatial origin, identify likely counterparts, test particle emission models. Using ∼120 ks XMM-Newton observations, we report discovery a pulsar wind nebula, possible counterpart for LHAASO PeVatron J0343+5254u. This extended source has power-law spectrum spectral index Γ X =...
We report the first detection of thermal X-ray line emission from supernova remnant (SNR) RX J1713.7-3946, prototype small class synchrotron-dominated SNRs. A softness-ratio map generated using XMM-Newton data shows that faint interior regions are softer than bright shell regions. Using Suzaku and deep observations, we have extracted spectra softest area, finding clear features at 1 ∼1.35 keV. These lines can be best explained as Ne Lyα Mg Heα a component. Since abundance ratios metals to Fe...
Supernova remnant (SNR) RX J1713.7-3946 is well known for its bright TeV gamma-ray emission with shell-like morphology. To constrain the hydrodynamical evolution, we have performed six times observations of northwestern (NW) shell Chandra X-ray Observatory from 2005 to 2011, and measured proper motion by using these data first epoch observation taken in 2000. The blast-wave shock speed at NW be $(3900\pm 300) (d/{\rm kpc})\ {\rm km}\ s}^{-1}$ an estimated distance $d = 1$ kpc, motions other...
Abstract Young supernova remnants (SNRs) are believed to be the origin of energetic cosmic rays (CRs) below “knee” their spectrum at ∼3 PeV (10 15 eV). Nevertheless, precise location, duration, and operation CR acceleration in young SNRs open questions. Here, we report on multiepoch X-ray observations Cassiopeia A (Cas A), a 350 yr old SNR, 15–50 keV band that probes most electrons. The observed flux decrease (15% ± 1% over 10 yr), contrary expected >90% based previous radio, X-ray,...
The Gamma-Ray and AntiMatter Survey (GRAMS) is a next-generation balloon/satellite mission utilizing Liquid Argon Time Projection Chamber (LArTPC) detector to measure both MeV gamma rays antinuclei produced by dark matter annihilation or decay. GRAMS can identify antihelium-3 events based on the measurements of X-rays charged pions from decay exotic atoms, Flight (TOF), energy deposition, stopping range. This paper shows sensitivity estimation using GEANT4 Monte Carlo simulation. For...
Abstract Pulsar halos are regions around middle-aged pulsars extending out to tens of parsecs. The large extent the and well-defined central cosmic-ray accelerators make this new class Galactic sources an ideal laboratory for studying transport. LHAASO J0621+3755 is a candidate pulsar halo associated with gamma-ray PSR J0622+3749. We observed VERITAS XMM-Newton in TeV X-ray bands, respectively. For work, we developed novel background estimation technique imaging atmospheric Cherenkov...
The shock waves of supernova remnants (SNRs) are prominent candidates for the acceleration Galactic cosmic rays. SNR RX J1713.7$-$3946 is one well-studied particle accelerator in our Galaxy because its strong non-thermal X-ray and gamma-ray radiation. We have performed NuSTAR (3-79 keV) observations northwest rim J1713.7$-$3946, where brightest part speed about 4000 km s$^{-1}$. spatially resolved emission from detected up to 20 keV first time. hard image 10-20 broadly similar soft-band 3-10...
Abstract The origin of the inner Galactic emission, measured by COMPTEL with a flux ∼10 −2 MeV cm s −1 sr in 1–30 energy range from region, has remained unsettled since its discovery. In this paper, we elaborate on model individual gamma-ray sources unresolved COMPTEL. This is conducted for crossmatched between Swift-BAT and Fermi-LAT catalogs interpolating spectra hard X-ray GeV ranges, as well unmatched two catalogs. We find that source contribution to emission would be at least ∼20%....
HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mo><</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>″</mml:mo></mml:mrow></mml:msup></mml:math> full width at half maximum) and broad spectral coverage (0.2–80 keV) with an effective area far superior to current facilities (including XMM -Newton NuSTAR ) enable revolutionary new...
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Abstract HESS J1641−463 is an unidentified gamma-ray source with a hard TeV spectrum, and thus it has been proposed to be possible candidate for cosmic-ray (CR) accelerator up PeV energies (a PeVatron candidate). The spatially coincides the radio supernova remnant G338.5+0.1 but not yet fully explored in X-ray band. We analyzed newly taken NuSTAR data, pointing at J1641−463, 82 ks effective exposure time. There no apparent counterpart of while nearby stellar cluster, Mercer 81, stray-light...
Abstract GRAMS (Gamma-Ray and AntiMatter Survey) is a next-generation balloon/satellite experiment utilizing LArTPC (Liquid Argon Time Projection Chamber), to simultaneously target astrophysical observations of cosmic MeV gamma-rays conduct an indirect dark matter search using antimatter. While LArTPCs are widely used in particle physics experiments, they have never been operated at balloon altitudes. An engineering flight with small-scale (eGRAMS) was conducted on July 27th, 2023, establish...
HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mo><</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>″</mml:mo></mml:mrow></mml:msup></mml:math> FWHM) and broad spectral coverage (0.2–80 keV) with an effective area far superior to current facilities (including XMM-Newton NuSTAR) enable revolutionary new insights into variety of...
The Gamma-Ray and AntiMatter Survey (GRAMS) project is a proposed next-generation balloon/satellite mission targeting both MeV gamma-ray observations antimatter-based dark matter searches. A cost-effective, large-scale Liquid Argon Time Projection Chamber (LArTPC) detector technology will allow GRAMS to have significantly improved sensitivity gamma rays while extensively probing parameter space via antimatter measurements.
The X-ray binary SS 433, embedded in the W50 nebula (or supernova remnant W50), shows bipolar jets that are ejected with mildly relativistic velocities, and extend toward east west out to scales of tens parsecs. Previous observations revealed twin lobes along jet precession axis contain compact bright knots dominated by synchrotron radiation, which provide evidence electron acceleration this system. Particle system is substantiated recently detected gamma rays energies up at least 25 TeV. To...
We report the results of a cross-match study between hard X-ray and GeV gamma-ray catalogs, by making use latest 105-month Swift-BAT 10-yr Fermi-LAT respectively. The spatial cross-matching two catalogs in matching 132 point-like sources, including ~5% false-match sources. Additionally, 24 sources that have been identified as same identifications are matched. Among 75 extended catalog, 31 coincidences with at least one source inside their extent. All matched consist blazars (>60%), pulsars...
GRAMS (Gamma-Ray and AntiMatter Survey) is a next-generation proposed balloon/satellite mission that will be the first to target both MeV gamma-ray observations antimatter-based indirect dark matter searches with LArTPC (Liquid Argon Time Projection Chamber) detector. Astrophysical at energies have been poorly explored long-neglected. With cost-effective, large-scale LArTPC, single LDB (Long-Duration Balloon) flight could provide an order of magnitude improved sensitivity compared previous...
Young supernova remnants (SNRs) are believed to be the origin of energetic cosmic rays (CRs) below "knee" their spectrum at $\sim3$ petaelectronvolt (PeV, $10^{15}$ eV). Nevertheless, precise location, duration, and operation CR acceleration in young SNRs open questions. Here, we report on multi-epoch X-ray observations Cassiopeia A (Cas A), a 350-year-old SNR, 15-50 keV band that probes most electrons. The observed flux decrease $(15\pm1\%)$, contrary expected $>$90\% based previous radio,...
Compact objects and supernova remnants provide nearby laboratories to probe the fate of stars after they die, way impact, are impacted by, their surrounding medium. The past five decades have significantly advanced our understanding these objects, showed that most relevant some mysterious energetic events in distant Universe, including Fast Radio Bursts Gravitational Wave sources. However, many questions remain be answered. These include: What powers diversity explosive phenomena across...
We study the supersymmetric Q balls which decay at present and find that they create a distinctive spectrum of gamma rays around O(10) MeV. The charge ball is lepton numbers in order for lifetime to be as long age universe, main products are light leptons. However, decreases, channel into pions becomes kinematically allowed towards end decay, produced rest. Immediately, $\pi^0$ decays two photons with energy 67.5 MeV, half pion mass, exhibits unique emission line. In addition, $\pi^\pm$...
HESS J1641-463 is an unidentified gamma-ray source with a hard TeV spectrum, and thus it has been proposed to be possible candidate for cosmic ray (CR) accelerators up PeV energies (a PeVatron candidate). The spatially coincides the radio supernova remnant (SNR) G338.5+0.1, but not yet fully explored in X-ray band. We analyzed newly taken NuSTAR data, pointing at J1641-463, 82 ks effective exposure time. There no apparent counterpart of while nearby stellar cluster, Mercer 81, stray-light...
We study the supersymmetric <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>Q</a:mi></a:math> balls which decay at present and find that they create a distinctive spectrum of gamma rays around O(10) MeV. The charge <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>Q</c:mi></c:math> ball is lepton numbers in order for lifetime to be as long age Universe, main products are light leptons. However, <e:math...