A5051819912- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Rare-earth and actinide compounds
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Iron-based superconductors research
- Particle accelerators and beam dynamics
- Stellar, planetary, and galactic studies
- X-ray Spectroscopy and Fluorescence Analysis
- Astro and Planetary Science
- Dark Matter and Cosmic Phenomena
- Ion-surface interactions and analysis
- SAS software applications and methods
- Plasma Diagnostics and Applications
- Advanced Polymer Synthesis and Characterization
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Electrostatics and Colloid Interactions
- Physics of Superconductivity and Magnetism
- Mass Spectrometry Techniques and Applications
- Advanced X-ray Imaging Techniques
- Photopolymerization techniques and applications
SPring-8
2014-2024
Doshisha University
2009-2024
National Astronomical Observatory of Japan
2016-2023
RIKEN
2004-2022
National Institute for Materials Science
2022
Tokyo Metropolitan University
2022
Institute of Particle and Nuclear Studies
2010-2020
High Energy Accelerator Research Organization
2008-2020
University of Utah
2013-2019
Kanagawa University
2016-2017
Photometric and spectroscopic data of the energetic Type Ic supernova (SN) 2002ap are presented, properties SN investigated through models its spectral evolution light curve. The is spectroscopically similar to "hypernova" 1997ef. However, kinetic energy [~(4-10) × 1051 ergs] mass ejected (2.5-5 M☉) smaller, resulting in a faster evolving synthesized ~0.07 M☉ 56Ni, peak luminosity was that normal SNe. Brightness alone should not be used define hypernova, whose defining character, namely very...
We present new spectroscopic and photometric data of the type Ibn supernovae 2006jc, 2000er 2002ao. discuss general properties this recently proposed supernova family, which also includes SN 1999cq. The early-time monitoring traces evolution class objects during first few days after shock breakout. An overall similarity in is found among members group, would be unexpected if energy these core-collapse events was dominated by interaction between ejecta circumstellar medium. Type appear to...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal degradation of polyacetylenes carrying substituentsToshio Masuda, Ben Zhong Tang, Toshinobu Higashimura, and Hitoshi YamaokaCite this: Macromolecules 1985, 18, 12, 2369–2373Publication Date (Print):December 1, 1985Publication History Published online1 May 2002Published inissue 1 December 1985https://pubs.acs.org/doi/10.1021/ma00154a006https://doi.org/10.1021/ma00154a006research-articleACS PublicationsRequest reuse permissionsArticle...
Interatomic Coulombic decay (ICD) from an Auger-final dicationic state is observed in the Ar dimer. A $2p$ inner-shell vacancy created by photoionization replaced with $3s$ and $3p$ vacancies via intra-atomic Auger decay. The subject to ICD which one of electrons same atom fills while neighboring emitted as electron. This process unambiguously identified electron-ion-ion coincidence spectroscopy kinetic energy electron release between ${\mathrm{Ar}}^{+}$ ${\mathrm{Ar}}^{2+}$ are measured coincidence.
view Abstract Citations (143) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Theoretical Light Curves for the Type IC Supernova SN 1994I Iwamoto, Kohichi ; Nomoto, Ken'ichi Höflich, Peter Yamaoka, Hitoshi Kumagai, Shiomi Shigeyama, Toshikazu in M 51 has provided light curves various wavelength bands allowing a distinction between models of Ic supernovae. We present bolometric and monochromatic exploding C+O stars that form from ~13-15 M_sun_...
Recent observations have revealed that Type Ia supernovae (SNe Ia) are not perfect standard candles; they show variations in their absolute magnitudes, light-curve shapes, and spectra. The C/O ratio the SNe progenitors (C-O white dwarfs) may be related to this variation. In work, we systematically investigate effects of stellar mass (M) metallicity (Z) on its distribution C-O dwarfs by calculating evolution from main sequence through end second dredge-up for M=3-9 M☉ Z=0.001-0.03. We find...
view Abstract Citations (132) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Theoretical Light Curves of Type IIb Supernova 1993J Shigeyama, Toshikazu ; Suzuki, Tomoharu Kumagai, Shiomi Nomoto, Ken'ichi Saio, Hideyuki Yamaoka, Hitoshi The observed feature the light curve SN 1993J, which has two maxima, are shown to be well reproduced by explosion red supergiant if its H/He envelope mass been decreased below ~0.9 M_sun_. first maximum is due...
We present optical and near-infrared observations of the dim afterglow GRB 020124, obtained between 2 68 hours after gamma-ray burst. The burst occurred in a very faint (R > 29.5) Damped Ly-alpha Absorber (DLA) at redshift z = 3.198 +- 0.004. derived column density neutral hydrogen is log(N_H) 21.7 0.2 rest-frame reddening constrained to be E(B-V) < 0.065, i.e., A_V 0.20 for standard extinction laws with R_V ~ 3. resulting dust-to-gas ratio less than 11 % that found Milky Way, but...
High-entropy-alloy (HEA) superconductors are a new class of disordered superconductors. However, commonality superconducting characteristics HEA materials is unclear. Here, we have investigated the crystal and electronic structure, robustness states in HEA-type metal telluride (MTe; M = Ag, In, Sn, Pb, Bi) under high pressure, results were compared with pressure effects for middle-entropy system (AgPbBiTe3) reference PbTe. When structure CsCl-type, all phases show superconductivity but...
Variable Star Network (VSNET, http://www.kusastro.kyoto-u.ac.jp/vsnet/) is a global professional-amateur network of researchers in variable stars and related objects, particularly transient such as cataclysmic variables, black hole binaries, supernovae gamma-ray bursts. The VSNET has been playing pioneering role establishing the field "transient object astronomy", by effectively incorporating modern advance observational astronomy electronic network, well collaborative progress theoretical...
view Abstract Citations (99) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Late Detonation Models for the Type IA Supernovae SN 1991T and 1990N Yamaoka, Hitoshi ; Nomoto, Ken'ichi Shigeyama, Toshikazu Thielemann, Friedrich-Karl We present hydrodynamical models of exploding white dwarf's to account newly observed premaximum features Ia supernovae in a unified manner. In these models, carbon deflagration, producing central Fe/Co/Ni core an...
view Abstract Citations (87) References (46) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Possible Models for the Type IA Supernova 1990N Shigeyama, Toshikazu ; Nomoto, Ken'ichi Yamaoka, Hitoshi Thielemann, Friedrich-Karl interpretations of new spectral and photometric features Ia supernova with carbon deflagration/detonation models are presented. To explain presence Si Ca at high expansion velocities in SN 1990N, we suggest four possible models, among...
We present ultraviolet (UV) spectroscopy and photometry of four Type Ia supernovae (SNe 2004dt, 2004ef, 2005M, 2005cf) obtained with the UV prism Advanced Camera for Surveys on Hubble Space Telescope. This data set provides unique spectral time series down to 2000 Å. Significant diversity is seen in near-maximum-light spectra (∼2000–3500 Å) this small sample. The corresponding photometric data, together archival from Swift Ultraviolet/Optical Telescope observations, provide further evidence...
Laser-excited N and R fluorescence lines of heavily doped ruby have been studied up to 26 GPa at low temperatures. While the intensity ambient pressure significantly decreases with decreasing temperature, originating from exchange-coupled Cr ion pairs is enhanced The induced wavelength shift 19 K well fitted an empirical formula similar equation for R1 line, showing that intense line could be used as alternative scale We also observe continuous increase in non-hydrostaticity increasing...
The energetics of the collision-induced dissociation fast C2H2+ ions into C2H+ + H and H+ (C2H) are determined from measurements translational energy fragments study influence ionizing electron energy, incident ion delay between production collision, nature target used. Evidence is given for occurrence three different processes: (i) electronic excitation to a dissociative state, (ii) adiabatic following momentum transfer, possibly (iii) predissociation, processes giving rise process C2H....
Valence instability is a key ingredient of the unusual properties f electron materials, yet clear understanding lacking as it involves complex interplay between electrons and conduc- tion states. Here we propose unified picture pressure-induced valence transition in Sm Yb monochalcogenides, considered model system for mixed valent 4f-electron materials. Using high-resolution x-ray absorption spectroscopy, show that driven by promotion 4f specifically into lowest unoccupied (LU) 5d t2g band....
We investigated the pressure dependence of electric transport and crystal structure Ag-doped $\mathrm{B}{\mathrm{i}}_{2}\mathrm{S}{\mathrm{e}}_{3}$. In sample prepared by Ag doping $\mathrm{B}{\mathrm{i}}_{2}\mathrm{S}{\mathrm{e}}_{3}$, Bi atom was partially replaced Ag, i.e., $\mathrm{A}{\mathrm{g}}_{0.05}\mathrm{B}{\mathrm{i}}_{1.95}\mathrm{S}{\mathrm{e}}_{3}$. X-ray diffraction patterns $\mathrm{A}{\mathrm{g}}_{0.05}\mathrm{B}{\mathrm{i}}_{1.95}\mathrm{S}{\mathrm{e}}_{3}$ measured at...