Yousuke Utsumi
A5082182459- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- CCD and CMOS Imaging Sensors
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Astrophysics and Star Formation Studies
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Inertial Sensor and Navigation
- Satellite Image Processing and Photogrammetry
- Dark Matter and Cosmic Phenomena
- Photocathodes and Microchannel Plates
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Optical Systems and Laser Technology
- Atmospheric Ozone and Climate
- GNSS positioning and interference
- Rheology and Fluid Dynamics Studies
National Astronomical Observatory of Japan
2008-2024
SLAC National Accelerator Laboratory
2018-2024
Kavli Institute for Particle Astrophysics and Cosmology
2017-2024
Stanford University
2017-2024
Menlo School
2024
Hiroshima University
2014-2020
Shanghai Astronomical Observatory
2016
The Graduate University for Advanced Studies, SOKENDAI
2008-2012
Nagoya University
2010
The University of Tokyo
2003
Abstract We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year catalog covering 137 deg2 of sky. Thanks to high effective galaxy number density ∼17 arcmin−2, even after conservative cuts such as a magnitude cut i < 24.5 and photometric redshift 0.3 ≤ z 1.5, we obtain high-significance measurement in four tomographic bins, achieving total signal-to-noise ratio 16 multipole range 300 ℓ 1900. carefully account for various...
Abstract The Hyper Suprime-Cam (HSC) is an 870 megapixel prime focus optical imaging camera for the 8.2 m Subaru telescope. wide-field corrector delivers sharp images of 0${^{\prime\prime}_{.}}$2 (FWHM) in HSC-i band over entire 1${^{\circ}_{.}}$5 diameter field view. collimation with respect to axis primary mirror done hexapod actuators, mechanical accuracy which a few microns. Analysis remaining wavefront error off-focus stellar reveals that components meets design specifications. While...
This paper presents the second data release of Hyper Suprime-Cam Subaru Strategic Program, a wide-field optical imaging survey on 8.2 meter Telescope. The includes from 174 nights observation through January 2018. Wide layer cover about 300 deg^2 in all five broadband filters (grizy) to nominal exposure (10min gr and 20min izy). Partially observed areas are also included release; 1100 is at least one filter exposure. median seeing i-band 0.6 arcsec, demonstrating superb image quality survey....
Hyper Suprime-Cam (HSC) is an 870 Mega pixel prime focus camera for the 8.2 m Subaru telescope. The wide field corrector delivers sharp image of 0.25 arc-sec FWHM in r-band over entire 1.5 degree (in diameter) view. collimation with respect to optical axis primary mirror realized by hexapod actuators whose mechanical accuracy few microns. As a result, we expect have seeing limited most time. Expected median 0.67 i-band. sensor p-ch fully depleted CCD 200 micron thickness (2048 x 4096 15 μm...
The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including nature dark matter and energy. has been awarded 300 nights observing time Telescope it started March 2014. This paper presents first public data release HSC-SSP. includes taken 1.7 years observations (61.5 nights) each Wide, Deep, UltraDeep layers covers about 108, 26, 4 square degrees down to depths i~26.4, ~26.5,...
Abstract This paper describes the detailed design of CCD dewar and camera system which is a part wide-field imager Hyper Suprime-Cam (HSC) on 8.2 m Subaru Telescope. On 1.°5 diameter focal plane (497 mm in physical size), 116 four-side buttable 2 k × 4 fully depleted CCDs are tiled with 0.3 gaps between adjacent chips, cooled down to −100°C by two pulse tube coolers capability exhaust 100 W heat at −100°C. The basically natural extension Suprime-Cam, incorporating some improvements such as...
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...
Abstract We have developed an automated quick data analysis system for quality assurance (QA) Hyper Suprime-Cam (HSC). The was commissioned in 2012–2014, and has been offered general observations, including the HSC Subaru Strategic Program, since 2014 March. provides observers with information, such as seeing, sky background level, transparency, based on are acquired. Quick-look images validation of image focus also provided through interactive web application. is responsible automatic...
ABSTRACT We report the discovery of 15 quasars and bright galaxies at 5.7 < z 6.9. This is initial result from Subaru High- Exploration Low-Luminosity Quasars project, which exploits exquisite multiband imaging data produced by Hyper Suprime-Cam (HSC) Strategic Program survey. The candidate selection performed combining several photometric approaches including a Bayesian probabilistic algorithm to reject stars dwarfs. spectroscopic identification was carried out with Gran Telescopio...
Abstract Recent detection of gravitational waves from a neutron star (NS) merger event GW170817 and identification an electromagnetic counterpart provide unique opportunity to study the physical processes in NS mergers. To derive properties ejected material merger, we perform radiative transfer simulations kilonova, optical near-infrared emissions powered by radioactive decays r-process nuclei synthesized merger. We find that observed emission lasting for &gt;10 d is explained 0.03 M⊙...
Abstract We present and characterize the catalog of galaxy shape measurements that will be used for cosmological weak lensing in Wide layer first year Hyper Suprime-Cam (HSC) survey. The covers an area 136.9 deg2 split into six fields, with a mean i-band seeing 0${^{\prime\prime}_{.}}$58 5σ point-source depth i ∼ 26. Given conservative selection criteria first-year science, excellent image quality results unweighted weighted source number densities 24.6 21.8 arcmin−2, respectively. define...
We report discovery of 41 new high-z quasars and luminous galaxies, which were spectroscopically identified at 5.7 < z 6.9. This is the fourth in a series papers from Subaru High-z Exploration Low-Luminosity Quasars (SHELLQs) project, based on deep multi-band imaging data collected by Hyper Suprime-Cam (HSC) Strategic Program survey. selected photometric candidates Bayesian probabilistic algorithm, then carried out follow-up spectroscopy with Gran Telescopio Canarias Telescope. Combined...
Abstract We report the discovery of 28 quasars and 7 luminous galaxies at 5.7 ≤ z 7.0. This is tenth in a series papers from Subaru High- Exploration Low-Luminosity Quasars (SHELLQs) project, which exploits deep multiband imaging data produced by Hyper Suprime-Cam (HSC) Strategic Program survey. The total number spectroscopically identified objects SHELLQs has now grown to 93 high- quasars, 31 galaxies, 16 [O iii ] emitters ∼ 0.8, 65 Galactic cool dwarfs (low-mass stars brown dwarfs). These...
Abstract We present the spectroscopic discovery of 69 quasars at 5.8 < z 7.0, drawn from Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) imaging survey data. This is 16th publication High- Exploration Low-Luminosity Quasars (SHELLQs) project, and it completes identification all but faintest candidates (i.e., i -band dropouts with AB 24 y detections, 24) Bayesian quasar probability <?CDATA ${P}_{Q}^{B}\gt 0.1$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
TiO(2) photocatalysts were successfully coated on silicone catheters or medical tubes by pretreatment of the surface with a sulfuric acid solution (5 M) for 3 h. The film adhered to substrate strongly against tensile and bending stresses. On TiO(2)-coated silicone-catheters under UV illumination, both bleaching methylene blue dye photocatalytic bactericidal effect Escherichia coli (E. coli) cells confirmed. Thus, this type catheter can be sterilized cleaned simply irradiation low-intensity...
We present DLSCL J0916.2+2951 (z=0.53), a newly discovered major cluster merger in which the collisional gas has become dissociated from collisionless galaxies and dark matter. identified using optical weak lensing observations as part of Deep Lens Survey. Our follow-up with Keck, Subaru, Hubble Space Telescope, Chandra show that is dissociative constrain matter self-interaction cross-section {\sigma}_{DM}m_{DM}^{-1}\leq7 cm^2g^{-1}. The system observed at least 0.7\pm0.2 Gyr since first...
We present new measurements of the quasar luminosity function (LF) at $z \sim 6$, over an unprecedentedly wide range rest-frame ultraviolet $M_{1450}$ from $-30$ to $-22$ mag. This is fifth in a series publications Subaru High-$z$ Exploration Low-Luminosity Quasars (SHELLQs) project, which exploits deep multi-band imaging data produced by Hyper Suprime-Cam (HSC) Strategic Program survey. The LF was calculated with complete sample 110 quasars $5.7 \le z 6.5$, includes 48 SHELLQs discovered...
We present spectroscopic identification of 32 new quasars and luminous galaxies discovered at 5.7 < z 6.8. This is the second in a series papers presenting results Subaru High-z Exploration Low-Luminosity Quasars (SHELLQs) project, which exploits deep multi-band imaging data produced by Hyper Suprime-Cam (HSC) Strategic Program survey. The photometric candidates were selected Bayesian probabilistic algorithm, then observed with spectrographs on Gran Telescopio Canarias Telescope. Combined...
QSOs have been thought to be important for tracing highly biased regions in the early universe, from which present-day massive galaxies and galaxy clusters formed. While overdensities of star-forming found around at 2<z<5, case excess clustering z>6 is less clear. Previous studies with HST reported detection small excesses faint dropout some QSO fields, but these surveys probed a relatively region surrounding QSOs. To overcome this problem, we observed most distant z=6.4 using large field...
We present the first results of a wide-field mapping survey M81 group conducted with Hyper Suprime-Cam on Subaru Telescope. Our deep photometry reaches $\sim2$ magnitudes below tip red giant branch (RGB) and reveals spatial distribution both old young stars over an area $\sim 100\times115$ kpc at distance M81. The ($\sim30-160$ Myr old) closely follow neutral hydrogen can be found in stellar stream between NGC\,3077 numerous outlying associations, including known concentrations Arp's Loop,...
We report the discovery of a quasar at z = 7.07, which was selected from deep multi-band imaging data collected by Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. This quasar, HSC J124353.93+010038.5, has an order magnitude lower luminosity than do other known quasars > 7. The rest-frame ultraviolet absolute is M1450 -24.13 +/- 0.08 mag and bolometric Lbol (1.4 0.1) x 10^{46} erg/s. Its spectrum in optical to near-infrared shows strong emission lines, evidence for fast gas...
Abstract We present the photometric properties of a sample infrared (IR) bright dust-obscured galaxies (DOGs). Combining wide and deep optical images obtained with Hyper Suprime-Cam on Subaru Telescope all-sky mid-IR (MIR) taken Wide-Field Infrared Survey Explorer, we discovered 48 DOGs i − Ks &gt; 1.2 [22] 7.0, where i, Ks, represent AB magnitude in i-band, Ks-band, 22 μm, respectively, GAMA 14 hr field (∼ 9 deg2). Among these objects, 31 65%) show power-law spectral energy...
Abstract We present the physical properties of AKARI sources without optical counterparts in images from Hyper Suprime-Cam (HSC) on Subaru telescope. Using infrared (IR) source catalog and HSC catalog, we select 583 objects that do not have North Ecliptic Pole wide survey field (∼5 deg 2 ). Because limiting magnitude is deep ( g AB ∼ 28.6), these are good candidates for extremely red star-forming galaxies (SFGs) and/or active galactic nuclei (AGNs), possibly at high redshifts. compile...
We present properties of moderately massive clusters galaxies detected by the newly developed Hyper Suprime-Cam on Subaru telescope using weak gravitational lensing. Eight peaks exceeding a signal-to-noise ratio (S/N) 4.5 are identified convergence S/N map 2.3 deg2 field observed during early commissioning phase camera. Multi-color photometric data used to generate optically selected Cluster finding algorithm based Multiband Identification Red-sequence algorithm. The optical cluster...
We present our optical follow-up observations to search for an electromagnetic counterpart of the first gravitational wave source GW150914 in framework Japanese collaboration Gravitational ElectroMagnetic (J-GEM), which is observing group utilizing and radio telescopes Japan, as well those New Zealand, China, South Africa, Chile, Hawaii. carried out a wide-field imaging survey with Kiso Wide Field Camera (KWFC) on 1.05-m Schmidt telescope Japan galaxy-targeted Tripole5 B&C 61-cm Zealand....