A5028251348- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Intermetallics and Advanced Alloy Properties
- Magnetic Properties of Alloys
- Semiconductor materials and interfaces
- Astrophysics and Star Formation Studies
- Physics of Superconductivity and Magnetism
- Advanced Thermoelectric Materials and Devices
- Advanced materials and composites
- Metallurgical and Alloy Processes
- Magnetic properties of thin films
- Hydrogen Storage and Materials
- Magnetic and transport properties of perovskites and related materials
- Magnetic Properties and Applications
- Powder Metallurgy Techniques and Materials
- High-Temperature Coating Behaviors
- High Temperature Alloys and Creep
- Astronomy and Astrophysical Research
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- Metallic Glasses and Amorphous Alloys
National Astronomical Observatory of Japan
2015-2024
The Graduate University for Advanced Studies, SOKENDAI
2007-2024
Yamaguchi University
2024
Tohoku University
2009-2024
Sapporo Kosei General Hospital
2020-2024
W.M. Keck Observatory
2024
Tokyo Metropolitan University
2023
Shinko Hospital
2023
Muroran Institute of Technology
2022
National Institutes of Natural Sciences
2019-2020
The first detected gravitational wave from a neutron star merger was GW170817. In this study, we present J-GEM follow-up observations of SSS17a, an electromagnetic counterpart SSS17a shows 2.5-mag decline in the $z$-band 1.7 days to 7.7 after merger. Such rapid is not comparable with supernovae light curves at any epoch. color also evolves rapidly and becomes redder for later epochs; $z-H$ changed by approximately 2.5 mag period 0.7 days. evolution both optical brightness are consistent...
The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of in 2017, at wavelength 1.3 mm, revealed ring-like structure, which was interpreted as gravitationally lensed emission around central hole3. Here we report images obtained 2018, 3.5 showing that the compact core spatially resolved. High-resolution imaging shows structure [Formula: see text] Schwarzschild radii diameter, approximately 50% larger than...
We report on results from new high-sensitivity, high-resolution 86GHz (3.5 millimeter) observations of the jet base in nearby radio galaxy M87, obtained by Very Long Baseline Array conjunction with Green Bank Telescope. The resulting image has a dynamic range exceeding 1500 to 1, highest ever achieved for this at frequency, resolving and imaging detailed formation/collimation structure down ~10 Schwarzschild radii (Rs). clearly confirms some important features known lower frequencies, i.e.,...
Abstract Stereospecific polymerization of deuterated methyl methacrylates, CH 2 C(CH 3 )‐COOCD , CD C(CD )COOCH and )COOCD which were prepared by the acetone–cyanohydrin method, carried out. From polarized infrared study polymethyl methacrylate its analogue, spectra stereo‐regular methacrylates tentatively assigned in 4000–400 cm. −1 region. The isotactic polymers are easily crystallized show intensity variations bands. These bands originate mainly from deformation vibrations α‐CH group,...
We investigated the detailed inner jet structure of M87 using Very Long Baseline Array data at 2, 5, 8.4, 15, 23.8, 43, and 86 GHz, especially focusing on multi-frequency properties radio core base. First, we measured a size region transverse to axis, defined as $W_{\rm c}$, each frequency \nu, found relation between c}$ $\nu$ c}(\nu) \propto \nu^{-0.71\pm0.05}$. Then, by combining c}(\nu)$ dependence position $r_{\rm c}(\nu)$, which was obtained our previous study, have constructed...
A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions tens milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up ~15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from September late November 2014, culminating in end-to-end observations, calibrations, imaging selected Science Verification (SV) targets. This paper presents an overview campaign its main results,...
We present a study of the sub-parsec scale radio structure galaxy 3C 84/NGC 1275 based on Very Long Baseline Array data at 43 GHz. discover limb brightening in "restarted" jet that is associated with 2005 outburst. In 1990s, was ridge rather than brightening, despite observations being done similar angular resolutions. This indicates transverse has recently changed. change morphology reveals an interesting agreement γ-ray flux increase, i.e., 1990s least seven times lower current one. One...
We present the large statistics of galaxy effective radius in rest-frame far-infrared (FIR) wavelength Re(FIR) obtained from 1627 deep ALMA 1-mm band maps that become public by 2017 July. Our sample consists 1034 sources at z=0-6 typically have star-formation rate ~100-1000 M$_{\odot}$/yr and stellar mass ~10$^{10}$-10$^{11.5}$ M$_{\odot}$. homogeneously derive FIR luminosity L_FIR our via same uv-visibility method with exponential disk fitting, carefully evaluating selection measurement...
The velocity field of the M87 jet from milli-arcsecond (mas) to arcsecond scales is extensively investigated together with new radio images taken by EVN observations. We detected proper motions components located at between 160 mas core and HST-1 complex for first time. Newly derived fields exhibits a systematic increase sub-to-superluminal speed in upstream HST-1. If we assume that observed velocities reflect bulk flow, here suggest may be gradually accelerated through distance 10^6 times...
We report on 230 GHz (1.3 mm) VLBI observations of M87 with the Event Horizon Telescope using antennas Mauna Kea in Hawaii, Mt. Graham Arizona and Cedar Flat California. For first time, we have acquired interferometric phase information through measurement closure triangle long baselines. Most measured phases are consistent 0$^{\circ}$ as expected by physically-motivated models for structure such jet accretion disk models. The brightness temperature event-horizon-scale is $\sim 1 \times...
We present ALMA observations of the [C ii] line and far-infrared (FIR) continuum a normally star-forming galaxy in reionization epoch, z = 6.96 Lyα emitter (LAE) IOK-1. Probing to sensitivities σline 240 μJy beam−1 (40 km s−1 channel) σcont 21 beam−1, we found undetected both continuum. Comparison ultraviolet (UV)–FIR spectral energy distribution (SED) IOK-1, including our limit, with those several types local galaxies (including effects cosmic microwave background, CMB, on FIR continuum)...
We present the polarization observations toward circumstellar disk around HD 142527 by using Atacama Large Millimeter/submillimeter Array (ALMA) at frequency of 343 GHz. The beam size is $0.51 " \times 0.44 "$, which corresponds to spatial resolution $\sim$ 71 $\times$ 62 AU. polarized intensity displays a ring-like structure with peak located on east side fraction $P= 3.26 \pm 0.02$ %, different from continuum emission northeast region. significantly weaker where 0.220 0.010$ %. vectors are...
We present statistics of 133 faint 1.2-mm continuum sources detected in about 120 deep ALMA pointing data that include all the archival available by 2015 June. derive number counts 1.2 mm down to 0.02 mJy partly with assistance gravitational lensing, and find total integrated flux securely identified is 22.9^(+6.7)_(-5.6) Jy deg^(-2) corresponds 104^(+31)_(-25) % extragalactic background light (EBL) measured COBE observations. These results suggest major EBL contributors are mJy, very ~<...
Abstract The mechanisms causing millimeter-wave polarization in protoplanetary disks are under debate. To disentangle the mechanisms, we observe disk around HL Tau at 3.1 mm with Atacama Large Millimeter/submillimeter Array (ALMA), which had detected CARMA 1.3 mm. We successfully detect ring-like azimuthal polarized emission This indicates that dust grains aligned major axis being direction, is consistent theory of radiative alignment elongated grains, where perpendicular to radiation flux....
Abstract The origin of polarized emission from protoplanetary disks is uncertain. Three mechanisms have been proposed for this emission: grain alignment with magnetic fields, radiation gradients, and self-scattering thermal dust emission. Aiming to observationally identify the polarization mechanisms, we present ALMA observations 0.87 mm continuum toward circumstellar disk around HD 142527 high spatial resolution. We confirm that vectors in northern region are consistent self-scattering....
Abstract The M87 jet is extensively examined by utilizing general relativistic magnetohydrodynamic (GRMHD) simulations, as well the steady axisymmetric force-free electrodynamic (FFE) solution. Quasi-steady funnel jets are obtained in GRMHD simulations up to scale of ∼100 gravitational radii ( r g ) for various black hole (BH) spins. As known, edge approximately determined following equipartitions: (i) magnetic and rest-mass energy densities (ii) gas pressures. Our numerical results give an...
We present ALMA Band 6 observations of the CO(2-1), HCN(3-2), and HCO$^{+}$(3-2) lines in nearby radio galaxy / brightest cluster (BCG) NGC 1275 with spatial resolution $\sim20$ pc. In previous observations, CO(2-1) emission was detected as radial filaments lying east-west direction. resolved inner filament found that cannot be represented by a simple infalling stream both morphologically kinematically. The observed complex nature resembles cold gas structure predicted recent numerical...
We have examined the phase equilibrium and thermoelectric properties of Co1−xFexSb3 ternary system up to high iron context x=0.40. Traces Sb were observed in hot-pressed samples with x⩾0.06, FeSb2 (Fe0.73Co0.27Sb2) compound marcasite structure was also x⩾0.25 by x-ray diffraction. The lattice parameter is slightly larger than that binary CoSb3. Seebeck coefficient electrical resistivity are generally reduced substitution for Co Fe. thermal conductivity especially at content region. These...
We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Faint Images Radio Sky at Twenty-centimeters (FIRST) Very Large Array (VLA), which increases number known NLS1s with kpc-scale to six, including two gamma-ray emitting (PMN J0948+0022 and 1H 0323+342) detected by Fermi Gamma-ray Space Telescope. The detection rate extended emissions is lower than that broad-line active galactic nuclei (AGNs) a statistical...