A5003969884- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Optical Coatings and Gratings
- Astrophysical Phenomena and Observations
- Photonic and Optical Devices
- Advanced optical system design
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Distributed and Parallel Computing Systems
- CCD and CMOS Imaging Sensors
- Planetary Science and Exploration
- Astrophysics and Cosmic Phenomena
- History and Developments in Astronomy
- Advanced Surface Polishing Techniques
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Spectroscopy and Laser Applications
- Optical Systems and Laser Technology
- Geophysics and Gravity Measurements
- Advanced Fiber Optic Sensors
National Astronomical Observatory of Japan
2014-2024
Shinshu University
2024
The Graduate University for Advanced Studies, SOKENDAI
2024
Tokyo Metropolitan University
2024
National Institutes of Natural Sciences
2022
Toyota Technological Institute
2019
The University of Tokyo
2018
Astronomical Observatory
2004-2017
Canon (Japan)
2017
Gunma Astronomical Observatory
2004
Abstract The primordial He abundance Y P is a powerful probe of cosmology. Currently, best determined by observations metal-poor galaxies, while there are only few known local extremely (<0.1 Z ⊙ ) galaxies (EMPGs) having reliable He/H measurements with i λ 10830 near-infrared (NIR) emission. Here we present deep Subaru NIR spectroscopy for 10 EMPGs. Combining the existing optical data, values 5 out EMPGs reliably derived Markov chain Monte Carlo algorithm. Adding 3 and 51 moderately...
Abstract We present the demography of dynamics and gas mass fraction 33 extremely metal-poor galaxies (EMPGs) with metallicities 0.015–0.195 Z ⊙ low stellar masses 10 4 –10 8 M in local universe. conduct deep optical integral field spectroscopy (IFS) for low-mass EMPGs medium-high resolution ( R = 7500) grism m Subaru FOCAS IFU instrument by EMPRESS 3D survey, investigate H α emission EMPGs. Exploiting high enough galaxies, we derive lines fitting three-dimensional disk models. obtain an...
Single-shot optical imaging based on ultrashort lasers has revealed nonrepetitive processes in subnanosecond timescales beyond the recording range of conventional high-speed cameras. However, nanosecond photography without sacrificing short exposure time and image quality is still missing because gap recordable between ultrafast electronic Here, we demonstrate ultrawide time-range using a spectrum circuit that produces interval-tunable pulse trains while keeping durations. We capture shock...
We present the H$\alpha$ intensity map of host galaxy repeating fast radio burst FRB 121102 at a redshift z=0.193 obtained with AO-assisted Kyoto 3DII optical integral-field unit mounted on 8.2-m Subaru Telescope. detected compact H$\alpha$-emitting (i.e., star-forming) region in galaxy, which has much smaller angular size [$< 0".57$ (1.9 kpc) full width half maximum (FWHM)] than extended stellar continuum emission determined by Gemini/GMOS z'-band image [$\simeq 1".4$ (4.6 FWHM ellipticity...
We performed Hα imaging observations of 22 luminous infrared galaxies to investigate how the distribution star-forming regions in these is related galaxy interactions. Based on correlation diagrams between flux and continuum emission for individual galaxies, a sequence was found: very compact (∼100 pc) nuclear starbursts with almost no activity outer (type 1), dominant ≲1 kpc size negligible contribution from 2), ≳1 significant 3), extended relatively faint nuclei 4). These classes were...
We present sequentially timed all-optical mapping photography (STAMP) with a slicing mirror in branched 4f system for an increased number of frames without sacrificing pixel resolution. The spectrally separates the laser light path into multiple paths by placed Fourier plane. Fabricated ultra-precision end milling process, has 18 facets differing angles. used boosted STAMP to observe dynamics ablation two image sensors which captured subsequent at frame rate 126 billion per second,...
The photovoltaic effect can occur without metal/semiconductor or semiconductor/semiconductor interfaces in materials with spontaneous electric polarization due to a lack of spatial inversion symmetry. This anomalous phenomenon is known as the bulk (BPV) owing shift current, which facilitates photoelectric conversion. Alpha-phase indium selenide (α-In2Se3) ferroelectric semiconductor polarization. Here, we report an experimental demonstration BPV α-In2Se3 films along out-of-plane direction by...
Integral Field Spectroscopy (IFS) is an observational method to obtain spatially resolved spectra over a specific field of view (FoV) in single exposure. In recent years, near-infrared IFS has gained importance observing objects with strong dust attenuation or at high redshift. One limitation existing instruments their relatively small FoV, less than 100 arcsec$^2$, compared optical instruments. Therefore, we have developed (0.9-2.5 $\mathrm{\mu}$m) image-slicer type integral unit (IFU)...
Abstract We present optical spectroscopic and photometric observations of Type Ia supernova (SN Ia) 2006X from 10 d before the $B$-band maximum to 91 after. This object exhibits one highest expansion velocities ever published for SNe Ia. At its premaximum phases, spectra show strong broad features intermediate-mass elements, such as Si, S, Ca, Mg, while Oi$\lambda$7773 line is weak. The extremely high Si ii S lines weak feature Oi suggest that an intense nucleosynthesis might take place in...
We present the optical observations of Near Earth Object 107P/(4015) Wilson–Harrington during 2009/2010 apparition taken in search low-level comet activity. Our photometric and spectroscopic data were collected 28–86 days after perihelion passage on 2009 October 22 a wide range solar phase angles 39°–68°. A disk-integrated function was constructed, giving geometric albedo 0.055 ± 0.012, integral q = 0.34, Bond AB 0.019. The property shows profile similar to low asteroids nuclei. No emission...
We have observed the central region of nearby starburst galaxy NGC 253 with Kyoto Tridimensional Spectrograph II (Kyoto3DII) Fabry-Perot mode in order to investigate properties its galactic wind. Since this has a large inclination, it is easy observe produced Ha, [N II]6583, and [S II]6716,6731 images, as well those line ratio maps. The II]/Ha wind larger than H regions disk. southeastern filament, part wind, largest reaches about 1.5. These ratios are explained by shock...
We report results of the 2006 April multi-wavelengths campaign SS 433, focusing on X-ray data observed with Suzaku at two orbital phases (in- and out-of- eclipse) simultaneous optical spectroscopic observations. By analyzing Fe25 K_alpha lines originating from jets, we detect rapid variability Doppler shifts, dz/dt ~ 0.019/0.33 day^-1, which is larger than those expected precession and/or nodding motion. This phenomenon probably corresponding to "jitter" motions for first time in X-rays,...
We present kinematics of 6 local extremely metal-poor galaxies (EMPGs) with low metallicities ($0.016-0.098\ Z_{\odot}$) and stellar masses ($10^{4.7}-10^{7.6} M_{\odot}$). Taking deep medium-high resolution ($R\sim7500$) integral-field spectra 8.2-m Subaru, we resolve the small inner velocity gradients dispersions EMPGs H$\alpha$ emission. Carefully masking out sub-structures originated by inflow and/or outflow, fit 3-dimensional disk models to observed flux, velocity, velocity-dispersion...
In order to investigate physical conditions of ionized gas in galaxies, as well its kinematics, we have developed the Kyoto tridimensional spectrograph II. It is a multimode optical instrument, including integral field (IFS) and Fabry-Perot imager modes. We designed it compact so that can mount on 2 m class telescopes 8.2 Subaru telescope. Special care was taken obtain high-quality calibrations IFS mode. remove chromatic aberration micropupil images produced by lenslet array, introduced...
We have obtained integral field spectra of the low-ionization emission-line region in galaxy NGC 1052 by using Kyoto Tridimensional Spectrograph II mounted on Subaru Telescope. Our high signal-to-noise ratio data with precise template subtraction revealed weaker features at nucleus, including [Fe III] and He emission lines, as well a broad component Hβ emission. The suggests existence broad-line region. spatial structure velocity derived from cube suggest three main components: high-velocity...
Abstract We present the results of photometric observations carried out with four small telescopes asteroid 4 Vesta in B, RC, and z ′ bands at a minimum phase angle 0$_{.}^{\circ}$1. The magnitudes, reduced to unit distance zero angle, were MB(1, 1, 0) = 3.83 ± 0.01, $M_{R_{\rm C}}$(1, 2.67 $M_{z^{\,\prime }}(1, 3.03\,\pm \,0.01\:$mag. absolute magnitude obtained from IAU H − G function is ∼ 0.1 mag darker than 0° determined Shevchenko Hapke models coherent backscattering effect term. Our...
ABSTRACT We present new observations of two $z$ = 0.12 strong-lensing elliptical galaxies, originally discovered from the SDSS-IV MaNGA survey, using FOCAS IFU spectrograph on Subaru Telescope. For J1436+4943, our confirm identification this system as a multiple-image lens, in cusp configuration, with an Einstein radius θEin 2.0 arcsec. J1701+3722, improved data earlier hints complex source plane, different configurations evident emission lines. The reveal previously unseen inner...
Abstract The Faint Object Camera and Spectrograph (FOCAS) is an optical imaging spectroscopy instrument for the Subaru Telescope. It has been a workhorse since first-light phase of telescope. We describe integral field unit (IFU) that recently installed in FOCAS. IFU utilizes image slicer divides ${13{^{\prime \prime }_{.}}5}$ × ${10{^{\prime }_{.}}0}$ view into 23 stripes, with width ${0{^{\prime }_{.}}435}$. A sky spectrum separated from object by approximately ${5{^{\prime }_{.}}2}$ can...
ISLE is a near-infrared imager and spectrograph for the Cassegrain focus (f/18) of 1.88 m telescope at Okayama Astrophysical Observatory. It upgraded instrument with new detector, HAWAII-1 HgCdTe array optics. provides imaging capabilities which covers 4.2 × arcmin<sup>2</sup> field-of-view 0.25 arc-sec/ pixel long-slit (4 arcmin) spectroscopic λ/Δλ = 1000 - 4000 using reflection gratings. The noise performance detector excellent. read 2.5 electrons 25 Fowler pairs has...
We present an innovative optical design for image slicer integral field unit (IFU) and manufacturing method which overcome limitation of metallic mirrors. Our IFU consists micro 45 arrayed highly-narrow flat mirrors a pseudo pupil mirror array off-axis conic aspheres forming three slits re-arranged images. A prototype demonstrates their quality high enough visible light spectrograph. The each is 1.58 mm in length 30μm width with surface roughness < 1 nm rms, edge sharpness 0.1μm, etc. This...
The Multi-Object Broadband Imaging Echellette (MOBIE) is the seeing-limited, visible-wavelength imaging multiobject spectrograph (MOS) planned for first-light use on Thirty Meter Telescope (TMT). MOBIE project to date has been a collaboration lead by UC Observatories (CA), and including UH Institute Astronomy (HI), NAOJ (Tokyo, Japan). current optical design provides two color channels, spanning 310–550nm 550-1000nm passbands, combination of reflection gratings, prisms, mirrors enable direct...
We report the initial result of an adaptive-optics assisted, optical integral-field-unit observation on IRAS04576+0912, nearest (z=0.039) active galactic nucleus with a prominent blueshift/tail in [O III] emission from sample such objects that we have collected literature. aim at addressing putative quasar-mode feedback process Subaru/Kyoto 3D II+AO188. The waveband (6400--7500 AA) enables us to measure gas density via [S II] doublets, contrast earlier Near-IR studies. Since fast outflow...
As a transmission grating, surface-relief (SR) grating with sawtooth shaped ridges and volume phase holographic (VPH) are widely used for instruments of astronomical observations. However the SR is difficult to achieve high diffraction efficiency at angular dispersion, VPH has low in orders. We propose novel gratings that solve these problems. introduce hybrid grism which combines refractive index prism replicated an acute apex angle. The birefringence (B-VPH) contains anisotropic medium,...
The primordial He abundance $Y_\mathrm{P}$ is a powerful probe of cosmology. Currently, best determined by observations metal-poor galaxies, while there are only few known local extremely ($<0.1 Z_\odot$) galaxies (EMPGs) having reliable He/H measurements with HeI$λ$10830 near-infrared (NIR) emission. Here we present deep Subaru NIR spectroscopy for 10 EMPGs. Combining the existing optical data, values 5 out EMPGs reliably derived Markov chain Monte Carlo algorithm. Adding 3 and 51...
Abstract We present the results of tridimensional spectrophotometric observations central region Seyfert galaxy NGC 1068 obtained by using Kyoto spectrograph I. A brief description instrument is presented. have found existence low-ionized gas extending out ionization cone. It characterized higher ([S II]$\lambda6716+\lambda6731) / \mathrm{H}\alpha$ than within The ratio peaks at $5{}^{\prime\prime} \hbox{--} 6{}^{\prime\prime}$ east and west nucleus reaches to 0.5–0.6. outside cone scattered...