Masami Ouchi
A5039711638- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Calibration and Measurement Techniques
- Photocathodes and Microchannel Plates
- Advanced Vision and Imaging
- Particle Detector Development and Performance
- History and Developments in Astronomy
- Real-time simulation and control systems
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Remote Sensing in Agriculture
- Plant Water Relations and Carbon Dynamics
The University of Tokyo
2015-2024
Kavli Institute for the Physics and Mathematics of the Universe
2015-2024
National Astronomical Observatory of Japan
2004-2024
The Graduate University for Advanced Studies, SOKENDAI
2022-2024
Purple Mountain Observatory
2024
Chinese Academy of Sciences
2024
Waseda University
2024
National Institutes of Natural Sciences
2019-2022
Carnegie Observatories
2008-2013
Space Telescope Science Institute
2005-2012
Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of 8.2m Subaru telescope summit Maunakea in Hawaii. A team scientists from Japan, Taiwan and Princeton University using HSC to carry out 300-night multi-band survey high-latitude sky. The includes three layers: Wide layer will cover 1400 deg$^2$ five broad bands ($grizy$), with $5\,\sigma$ point-source depth $r \approx 26$. Deep covers total 26~deg$^2$ four fields, going roughly magnitude fainter, while UltraDeep goes...
Abstract We have built an 80-mega pixels ($10240 \times 8192$) mosaic CCD camera, called Suprime-Cam, for the wide-field prime focus of 8.2 m Subaru telescope. Suprime-Cam covers a field view $34' 27'$, unique facility among 8–10 class telescopes, with resolution ${0\rlap {.}{}^{\mathrm {\prime \prime }}202}$ per pixel. The focal plane consists ten high-resistivity $2\mathrm{k} 4\mathrm{k}$ CCDs developed by MIT Lincoln Laboratory, which are cooled large Stirling-cycle cooler. readout...
We present Lya luminosity function (LF), clustering measurements, and line profiles based on the largest sample, to date, of 207 emitters (LAEs) at z=6.6 1-deg^2 sky Subaru/XMM-Newton Deep Survey (SXDS) field. Our LF including cosmic variance estimates yields best-fit Schechter parameters phi*=8.5 +3.0/-2.2 x10^(-4) Mpc^(-3) L*(Lya)=4.4 +/-0.6 x10^42 erg s^(-1) with a fixed alpha=-1.5, indicates decrease from z=5.7 >~90% confidence level. However, this is not large, only =~30% in luminosity,...
Understanding cosmic reionization requires the identification and characterization of early sources hydrogen-ionizing photons. The 2012 Hubble Ultra Deep Field (UDF12) campaign has acquired deepest infrared images with Wide Camera 3 aboard Space Telescope and, for first time, systematically explored galaxy population deep into era when microwave background (CMB) data indicates was underway. UDF12 thus provides best constraints to date on abundance, luminosity distribution, spectral...
We present the results of deepest search to date for star-forming galaxies beyond a redshift z~8.5 utilizing new sequence near-infrared Wide Field Camera 3 images Hubble Ultra Deep Field. This `UDF12' campaign completed in September 2012 doubles earlier exposures with WFC3/IR this field and quadruples exposure key F105W filter used locate such distant galaxies. Combined additional imaging F140W filter, fidelity high candidates is greatly improved. Using spectral energy distribution fitting...
We present luminosity functions (LFs) and various properties of Lya emitters (LAEs) at z=3.1, 3.7, 5.7, in a 1 deg^2 sky the Subaru/XMM-Newton Deep Survey (SXDS) Field. obtain photometric sample 858 LAE candidates based on deep Subaru/Suprime-Cam imaging data, spectroscopic 84 confirmed LAEs from Subaru/FOCAS VLT/VIMOS spectroscopy survey volume ~10^6 Mpc^3 with limiting ~3x10^42 erg/s. derive LFs UV-continuum (~1500 Å) for each redshift, taking into account statistical error field-to-field...
We investigate the photometric properties of Lyman break galaxies (LBGs) at z = 3.5-5.2 based on large samples 2600 LBGs detected in deep (i' ≲ 27) and wide-field (1200 arcmin2) images taken Subaru Deep Field (SDF) Subaru/XMM-Newton (SXDF) using broadband B, V, R, i', z' filters. The selection criteria for LBG are examined with 85 spectroscopically identified objects, completeness contamination estimated from Monte Carlo simulations a photometric-redshift catalog Hubble Field-North. find...
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....
We report an extensive search for Lyman-alpha emitters (LAEs) at z=6.5 in the Subaru Deep Field. Subsequent spectroscopy with and Keck identified eight more LAEs, giving a total of 17 spectroscopically confirmed LAEs z=6.5. Based on this spectroscopic sample 17, complemented by photometric 58 we have derived accurate luminosity function z=6.5, which reveals apparent deficit bright end ~0.75 mag fainter L*, compared that observed z=5.7. The difference LAE functions between z=5.7 6.5 is...
We present the results of our ultra-deep Keck/DEIMOS spectroscopy z-dropout galaxies in SDF and GOODS-N. For 3 out 11 objects, we detect an emission line at ~ 1um with a signal-to-noise ratio 10. The lines show asymmetric profiles high weighted skewness values, consistent being Lya, yielding redshifts z=7.213, 6.965, 6.844. Specifically, confirm z=7.213 object two independent DEIMOS runs different spectroscopic configurations. z=6.965 is known Lya emitter, IOK-1, for which improved spectrum...
We present a new determination of the ultraviolet (UV) galaxy luminosity function (LF) at redshift z ≃ 7 and 8, first estimate 9. An accurate form evolution LF during this era is key importance for improving our knowledge earliest phases process cosmic reionization. Our analysis exploits to full new, deepest Wide Field Camera 3/infrared imaging from Hubble Space Telescope (HST) Ultra-Deep 2012 (UDF12) campaign, with dynamic range provided by including consistent all appropriate,...
We present the redshift evolution of galaxy effective radius re obtained from Hubble Space Telescope (HST) samples ∼190,000 galaxies at z = 0–10. Our HST consist 176,152 photo-z 0–6 3D-HST+CANDELS catalog and 10,454 Lyman break (LBGs) 4–10 identified in Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), HUDF 09/12, HFF parallel fields, providing largest data set to date for size studies. derive with same technique over wide range 0–10, evaluating optical-to-UV...
We conduct a comprehensive study on dropout galaxy candidates at $z\sim9-16$ using the first 90 arcmin$^2$ JWST/NIRCam images taken by early release observations (ERO) and science (ERS) programs. With JWST simulation images, we find that number of foreground interlopers are selected with weak photo-$z$ determination ($\Delta\chi^2>4$). thus carefully apply secure selection criterion ($\Delta\chi^2>9$) conventional color criteria confirmations ERO NIRSpec spectroscopic redshifts, obtain total...
Abstract The Subaru Prime Focus Spectrograph (PFS) is a massively multiplexed fiber-fed optical and near-infrared three-arm spectrograph (Nfiber = 2400, 380 ≤ λ 1260 nm, 1 $_{.}^{\circ}$3 diameter field of view). Here, we summarize the science cases in terms provisional plans for 300-night survey. We describe to constrain nature dark energy via survey emission line galaxies spanning comoving volume 9.3 h−3 Gpc3 redshift range 0.8 < z 2.4. In each six bins, cosmological distances will...
We present results from a new Keck spectroscopic survey of UV-faint LBGs in the redshift range 3<z<7. Combined with earlier and published ESO VLT data, our sample contains more than 600 dropouts, offering insight into nature sub-L* sources typical those likely to dominate cosmic reionisation process. Here we use this characterise fraction strong Lya emitters within continuum-selected dropouts. By quantifying how "Lya fraction" varies redshift, seek constrain changes transmission associated...
We present a systematic study for ionization state of inter-stellar medium in galaxies at z=0-3 with ~140,000 SDSS and 108 intermediate to high redshift from the literature, using an ionization-parameter sensitive line ratio [OIII]5007/[OII]3727 photoionization models. confirm that z=2-3 show [OIII]/[OII] significantly higher than typical star-forming galaxy by factor >~10, models reveal these high-z have parameter log(qion/cm s^{-1})~7.6-9.0, ~4-10 local galaxies. For any redshift, we...
As Lyα photons are scattered by neutral hydrogen, a change with redshift in the equivalent width (EW) distribution of distant galaxies offers promising probe degree ionization intergalactic medium and hence when cosmic reionization ended. This simple test is complicated fact that emission can also be affected variations kinematics dust content host galaxies. In first paper this series, we demonstrated both luminosity- redshift-dependent trend fraction emitters seen within color-selected...
The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, Chandra Field South, COSMOS, Hubble North, and Groth Strip. SEDS covers total area of 1.46 deg2 to depth 26 AB mag (3σ) in both warm Infrared Array Camera (IRAC) bands at 3.6 4.5 μm. Because its uniform coverage so many widely-separated fields, subject roughly 25% smaller errors due cosmic variance than single-field same size. was designed...
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,...
We carried out extended spectroscopic confirmations of Ly-alpha emitters (LAEs) at z=6.5 and 5.7 in the Subaru Deep Field. Now, total number spectroscopically confirmed LAEs is 45 54 5.7, respectively, least 81% (70%) our photometric candidates (5.7) have been identified as real LAEs. made careful measurements luminosity, both photometrically spectroscopically, to accurately determine rest-UV luminosity functions (LFs). The substantially improved evaluation LF shows an apparent deficit from...
Abstract This paper presents the third data release of Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a wide-field multi-band imaging survey with 8.2 m telescope. HSC-SSP has three layers (Wide, Deep, and UltraDeep) different area coverages depths, designed to address wide array astrophysical questions. from includes 278 nights observing time covers about 670 deg2 in all five broad-band filters (grizy) at full depth (∼26 mag 5σ depending on filter) Wide layer. If we include partially...
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...
We compute the spherically-averaged power spectrum from four seasons of data obtained for Epoch Reionisation (EoR) project observed with Murchison Widefield Array (MWA). measure EoR over $k= 0.07-3.0~h$Mpc$^{-1}$ at redshifts $z=6.5-8.7$. The largest aggregation 110 hours on EoR0 high-band (3,340 observations), yields a lowest measurement (43~mK)$^2$ = 1.8$\times$10$^3$ mK$^2$ $k$=0.14~$h$Mpc$^{-1}$ and $z=6.5$ (2$\sigma$ thermal noise plus sample variance). Using Real-Time System to...
Abstract We present the first statistical sample of faint type 1 AGNs at z > 4 identified by JWST/NIRSpec deep spectroscopy. Among 185 galaxies spec = 3.8–8.9 confirmed with NIRSpec, our systematic search for broad-line emission reveals 10 4.015–6.936 whose broad component is only seen in permitted H α line and not forbidden [O iii ] λ 5007 that detected greater significance than . The widths FWHM ≃ 1000–6000 km s −1 suggest have low-mass black holes M BH ∼ 6 –10 8 ⊙ , remarkably lower...