A5055328011- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- SAS software applications and methods
- Planetary Science and Exploration
- Astronomy and Astrophysical Research
- Semiconductor Lasers and Optical Devices
- Fluid Dynamics and Mixing
- Particle Detector Development and Performance
- Cyclone Separators and Fluid Dynamics
- Semiconductor Quantum Structures and Devices
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Photonic and Optical Devices
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- GaN-based semiconductor devices and materials
- Ionosphere and magnetosphere dynamics
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Space Science and Extraterrestrial Life
- Radiation Detection and Scintillator Technologies
- Geomagnetism and Paleomagnetism Studies
- Semiconductor materials and devices
- Fluid Dynamics and Turbulent Flows
The University of Tokyo
1974-2025
Tohoku University
2009-2024
Osaka University
2014-2024
Japan Aerospace Exploration Agency
2024
Tohoku Institute of Technology
2024
Tokyo University of Science
2001-2024
Laboratoire atmosphères, milieux, observations spatiales
2021-2023
Sorbonne Université
2021-2023
Centre National de la Recherche Scientifique
2021-2023
University of Tsukuba
2005-2023
The newly synthesized Keio Fluors, which are based on boron-dipyrromethene (BDP), have excellent and useful optical properties: vivid colors sharp emission in the visible−near-infrared region (583−738 nm), high quantum yields (Φ: 0.56−0.98), extinction coefficients (185000−288000 M-1 cm-1), good photostabilities. These properties superior to many of existing fluorescent dyes such as rhodamines, cyanines, or other BDP-based dyes.
A new series of high-performance fluorophores named Keio Fluors (KFL), which are based on borondipyrromethene (BODIPY), reported. The KFL dyes cover a wide spectral range from the yellow (547 nm) to near-infrared (NIR, 738 region, and their emission wavelength could be easily subtly controlled simple molecular modifications only, without losing optical properties. This "tailor-made" synthetic strategy for tuning enabled creation fourteen with well-controlled colors (yellow, orange, red,...
Using stacks of Lyα images 2128 emitters (LAEs) and 24 protocluster UVselected galaxies (LBGs) at z = 3.1, we examine the surface brightness profiles haloes around high-z as a function environment UV luminosity.We find that slopes radial become flatter Mpc-scale LAE densities increase, but they are almost independent central luminosities.The characteristic exponential scale lengths appear to be proportional square (r ∝ Σ 2 ).Including diffuse, extended haloes, rest-frame equivalent width...
We present results of a survey for giant Ly-alpha nebulae (LABs) at z=3 with Subaru/Suprime-Cam. obtained imaging z=3.09+-0.03 around the SSA22 protocluster and in several blank fields. The total area is 2.1 square degrees, corresponding to comoving volume 1.6 x 10^6 Mpc^3. Using uniform detection threshold 1.4 10^{-18} erg s^{-1} cm^{-2} arcsec^{-2} images, we construct sample 14 LAB candidates major-axis diameters larger than 100 kpc, including five previously known blobs two quasars. This...
We present the results of extensive narrow-band survey Ly\alpha\ emission-line objects at z=3.1 in 1.38 deg^2 area surrounding high density region star-forming galaxies z=3.09 SSA22 field, as well 1.04 three separated general blank fields. In total 2161 emitters, 1394 fields and 767 fields, respectively, are detected to AB magnitude limit 25.73, which corresponds line flux 1.8 x 10^{-17} erg s^{-1} cm^{-2} or luminosity 1.5 10^{42} z=3.1, above observed equivalent width threshold, 190\AA ....
Abstract The isotopic signature of atmospheric carbon offers a unique tracer for the history Martian atmosphere and origin organic matter on Mars. photolysis CO 2 is known to induce strong fractionation between CO. However, its effects compositions in remain uncertain. Here, we develop 1D photochemical model consider via , estimate vertical profiles atmosphere. We find that depleted 13 C compared with at each altitude, due photolysis: minimum value δ about −170‰ under standard eddy diffusion...
This paper treats the flow instabilities in a vaned diffuser by using CFD. A commercial code with standard κ-ε turbulence model was used for present work. It found that diffuser: i.e., rotating stall, alternate blade and asymmetric could be simulated calculations. These were observed range negative slope of pressure performance curve diffuser. The stall onset rate is larger case clearance between impeller vanes.
We present the results of an intermediate resolution (~2 angstrom) spectroscopy a sample 37 candidate Lyman alpha blobs and emitters at redshift z=3.1 using DEIMOS spectrograph on 10 m Keck telescope. The emission lines are detected for all objects have variety in their line profiles. velocity widths (FWHM) 28 with higher quality spectra, measured by fitting single Gaussian profile, range 150 - 1700 km/s correlate spatial extents. All 12 (>16 arcsec^2) large > 500 km/s. While there...
This Article reports the experimental study on dissociation and flame propagation characteristics of methane hydrate in a laminar boundary layer over horizontal flat plate. Experiments were performed at room temperature under atmospheric pressure using crystals that initially stored liquid-nitrogen temperature. The packed an insulated rectangular cell such surface was flush with air supplied plate from blower through orifice, settling chamber, converging nozzle. dissociating ignited...
Abstract The Solar Energetic Particle and imaging ultraviolet spectrograph (IUVS) instruments onboard the Mars Atmosphere Volatile EvolutioN (MAVEN) spacecraft discovered diffuse aurora that span across nightside of due to interaction solar energetic particles (SEPs) with Martian atmosphere. However, it is unclear whether originates from electrons or protons. We have developed a Monte Carlo model calculate limb intensity profile CO 2 + doublet (UVD) precipitation protons energy ranges 100 eV...
Abstract The dynamics of giant planet magnetospheres is controlled by a complex interplay between their fast rotation, interaction with the solar wind, and diverse internal plasma momentum sources. In ionosphere, Hall Pedersen conductances are two key parameters that regulate intensity currents coupling magnetosphere rate angular transfer power carried these currents. We perform comparative study conductivities in four planets our Solar System ‐ Jupiter, Saturn, Uranus Neptune. use generic...
Abstract Martian diffuse auroras are ultraviolet emissions spread across the nightside of Mars caused by solar energetic particles (SEP), both electrons and protons. The structures induced crustal magnetic fields expected to affect auroral emission profiles electrons, which is far from understood. Here we estimate field effects on based a newly developed Monte Carlo model simulating collisions electron cyclotron motions. Parameter surveys intensity dip angle (angle line horizontal direction)...
We report high quality GaAs/Ge/GaAs heterojunctions grown by molecular-beam epitaxy. Antiphase domain (APD) free GaAs on Ge growth, as verified high-energy electron diffraction and transmission microscopy, has been achieved for epitaxial (100) surfaces misoriented towards [011] while APDs are observed to annihilate after roughly 500 Å of growth nominally Ge. The outdiffusion Ga As into was investigated in situ x-ray photoemission spectroscopy secondary ion mass spectroscopy. electrical...
We present the discovery of a candidate giant radio-quiet Lyman-alpha (Lya) blob (RQLAB) in large-scale structure around high-redshift radio galaxy (HzRG) lying Lya halo, B3 J2330+3927 at redshift z=3.087. obtained imaging with Subaru/Suprime-Cam to search for emitters (LAEs) and absorbers (LAAs) z=3.09+-0.03. detected 127 LAEs 26 LAAs field view 31' x 24'. found that is surrounded by 130 kpc halo (60 20 comoving Mpc) filamentary structure. The contains one prominent local density peak an...
Deep narrowband (NB359) imaging with Subaru telescope by Iwata et al. have detected surprisingly strong Lyman continuum (LyC; ∼ 900 Å in the rest-frame) from some α emitters (LAEs) at z = 3.1.However, a possibility of redshift misidentification was not rejected previous spectroscopy due to narrow wavelength coverage.We here present results new deep covering observed 4,000-7,000 VLT/VIMOS and Subaru/FOCAS 8 LAEs NB359.All eight objects only one detectable emission line around 4,970 which is...
Formaldehyde (H2CO) is a critical precursor for the abiotic formation of biomolecules, including amino acids and sugars, which are building blocks proteins RNA. Geomorphological geochemical evidence on Mars indicates temperate environment compatible with existence surface liquid water during its early history at 3.8-3.6 billion years ago (Ga), was maintained by warming effect reducing gases, such as H2. However, it remains uncertain whether weakly suitable producing H2CO. In this study, we...
The atmospheric response to solar energetic particle (SEP) events has been studied in depth on Earth, but far less extensively Mars. Understanding the Martian atmosphere's SEP gives insight into how external forcing affects photochemical balance atmosphere. from 2004 2024 were identified using error logs Mars Express. This methodology contributed developing a comprehensive database of confirmed space weather We analysed data spectrometers NOMAD and SPICAM onboard ExoMars Trace Gas Orbiter...
We investigated the infrared optical spectra of an organic dimer Mott insulator $\ensuremath{\kappa}\mathrm{\text{\ensuremath{-}}}(\mathrm{BEDT}\mathrm{\text{\ensuremath{-}}}\mathrm{TTF}{)}_{2}\mathrm{Cu}[\mathrm{N}(\mathrm{CN}{)}_{2}]\mathrm{Cl}$, which was irradiated with x rays. observed that irradiation caused a large spectral weight transfer from midinfrared region, where interband transitions in and Mott-Hubbard bands take place, to Drude part low-energy region; this gap collapse. The...
The Magnéli phase Ti(4)O(7) exhibits two sharp jumps in resistivity with coupled structural transitions as a function of temperature at T(c1) approximately 142 K and T(c2) = 154 K. We have studied electronic structure changes across the using 7 eV laser, soft x-ray, hard x-ray (HX) photoemission spectroscopy (PES). Ti 2p-3d resonant PES HX show clear metallic Fermi edge mixed valency above T(c2). low below shows insulating gap 100 meV. intermediate between indicates pseudogap coexisting...
Abstract Ionospheric Pedersen and Hall conductances play significant roles in electromagnetic coupling between the planetary ionosphere magnetosphere. Several observations models have suggested existence of meteoric ions with interplanetary origins lower part Jupiter’s ionosphere; however, no considered contributions to ionospheric conductance. This study is designed evaluate contribution conductance by developing an model combining a meteoroid ablation photochemical model. We find that...
Flow instability in a vaned diffuser with an even number of blades was examined experimentally and analytically. In the experiments, alternate blade stall, asymmetric two types rotating stalls (backward/forward stall) were observed depending on impeller/diffuser clearance. For narrow clearance strong interaction, stall backward mainly occurred. With increasing clearance, forward also occurred, onset shifted toward higher flow rate corresponding to pressure performance diffuser. Simple 2D...
We present the results of our wide-field narrowband imaging field around radio galaxy 53W002 at z = 2.390 with Subaru/Suprime-Cam. A custom-made filter, NB413, centered 4140 Å a width 83 is used to observe 31' × 24' area galaxy. detected 204 Lyα emitters (LAEs) 2.4 rest-frame equivalent larger than 25 depth 26 AB mag (in NB413). The entire LAE population in has an average number density and distributions size that are similar those other fields ∼ 2. identify significant high-density region...