Satoshi Kikuta
A5019185776- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Cosmology and Gravitation Theories
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Advanced Vision and Imaging
- Particle Accelerators and Free-Electron Lasers
- Particle physics theoretical and experimental studies
- Advanced Fluorescence Microscopy Techniques
- Aluminum Alloys Composites Properties
- Advanced Welding Techniques Analysis
- Photocathodes and Microchannel Plates
- Scientific Research and Discoveries
National Astronomical Observatory of Japan
2017-2024
The University of Tokyo
2024
University of Tsukuba
2020-2023
The Graduate University for Advanced Studies, SOKENDAI
2016-2020
Nippon Soken (Japan)
2020
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....
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 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 quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars 6.55 < 7.15. The sample of 22 from Subaru High- Exploration Low-Luminosity Quasars (SHELLQs) project, combined 13 brighter in literature, covers an unprecedentedly wide range rest-frame ultraviolet magnitudes over −28 M 1450 −23. found that binned LF flattens significantly toward faint end populated by SHELLQs quasars. A maximum likelihood fit to a double power-law model...
Abstract We present luminosity functions (LFs) and angular correlation (ACFs) derived from 18,960 Ly α emitters (LAEs) at z = 2.2−7.3 over a wide survey area of ≲24 deg 2 that are identified in the narrowband data HSC-SSP CHORUS surveys. Confirming large sample with 241 spectroscopically LAEs, we determine LFs ACFs brighter range down to 0.5 L ⋆ , confirm our measurements consistent previous studies but offer significantly reduced statistical uncertainties. The improved precision allows us...
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...
Abstract We constrain the quasar contribution to cosmic reionization based on our deep optical survey of z ∼ 6 quasars down R = 24.15 using Subaru/Suprime-Cam in three UKIDSS-DXS fields covering 6.5 deg 2 . In Kashikawa et al. (2015), we select 17 candidates and report initial discovery two low-luminosity ( ) from seven targets, one which might be a Ly α -emitting galaxy. From an additional spectroscopy, none four out remaining 10 turn genuine quasars. Moreover, deeper photometry provided by...
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"...
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 second NuSTAR and XMM-Newton extragalactic survey of JWST north ecliptic pole (NEP) time-domain field (TDF). The first NEP-TDF had 681 ks total exposure time executed in cycle 5 2019 2020. This survey, acquired from 2020 to 2022 6, adds 880 time. overall is most sensitive date, a 60 sources were detected above 95% reliability threshold. constrain hard X-ray number counts, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi>...
The James Webb Space Telescope Time-Domain Field (JWST-TDF) is an $\sim$14$'$ diameter field near the North Ecliptic Pole that will be targeted by one of JWST Guaranteed Time Observations programs. Here, we describe our Clerk Maxwell SCUBA-2 850 $\mu$m imaging JWST-TDF and present submillimeter source catalog properties. We also a radio sources from Karl J. Jansky Very Large Array 3 GHz observations field. These were obtained to aid JWST's study dust-obscured galaxies contribute...
Abstract We report the large scale structure and clustering analysis of Ly α emitters (LAEs) blobs (LABs) at z = 2.2–2.3. Using 3341 LAEs, 117 LABs, 58 bright (Ly luminosity L > 10 43.4 erg s −1 ) LABs 2.2–2.3 selected with Subaru/Hyper Suprime-Cam, we calculate LAE overdensity to investigate 2. show that 79% 83% are located in overdense regions, which is consistent trend found by previous studies generally regions. find one our eight fields, dubbed J1349, contains 39/117 ≈ 33% 22/58 38%...
Abstract We present wide-field mapping at 850 μ m and 450 of the z = 2.85 protocluster in HS 1549+19 field using Submillimetre Common-User Bolometer Array 2. Spectroscopic follow-up 18 bright sources selected m, Northern Extended Millimeter Atacama Large Millimeter/submillimeter Array, confirms that majority lie near ≃ are likely members structure. Interpreting spectroscopic redshifts as distance measurements, we find submillimeter galaxies (SMGs) span 123 pMpc 2 plane sky demarcate a 3600 3...
Active galactic nuclei (AGNs) in the high-redshift Universe are thought to reside overdense environments. However, recent works provide controversial results partly due use of different techniques and possible suppression nearby galaxy formation by AGN feedback. We conducted deep wide-field imaging observations with Suprime-Cam on Subaru telescope searched for Lyman-alpha emitters (LAEs) around two QSOs (quasi-stellar objects) at $z\sim4.9$ a radio $z\sim4.5$ using narrow-band filters...
Abstract We present a new catalog of 9318 Ly α emitter (LAE) candidates at z = 2.2, 3.3, 4.9, 5.7, 6.6, and 7.0 that are photometrically selected by the SILVERRUSH program with machine learning technique from large area (up to 25.0 deg 2 ) imaging data six narrowband filters taken Subaru Strategic Program Hyper Suprime-Cam intensive program, Cosmic HydrOgen Reionization Unveiled Subaru. construct convolutional neural network distinguishes between real LAEs contaminants completeness 94%...
Abstract We conduct intensity mapping to probe for extended diffuse Ly α emission around emitters (LAEs) at z ∼2−7, exploiting very deep (∼26 mag 5 σ ) and large-area (∼4.5 deg 2 Subaru/Hyper Suprime-Cam narrowband (NB) images large LAE catalogs consisting of a total 1540 LAEs = 2.2, 3.3, 5.7, 6.6 obtained by the HSC-SSP CHORUS projects. calculate spatial correlations these with ∼1–2 billion pixel flux values NB images, deriving average surface brightness (SB radial profiles LAEs. By...
Abstract We present 20,567 Ly α emitters (LAEs) at z = 2.2 − 7.3 that are photometrically identified by the SILVERRUSH program in a large survey area up to 25 deg 2 with deep images of five broadband filters ( grizy ) and seven narrowband targeting lines 2.2, 3.3, 4.9, 5.7, 6.6, 7.0, taken Hyper Suprime-Cam Subaru Strategic Program Cosmic HydrOgen Reionization Unveiled survey. select secure >5 σ sources showing color excesses via break screening, taking into account spatial inhomogeneity...
Understanding how QSO's UV radiation affects galaxy formation is vital to our understanding of reionization era. Using a custom made narrow-band filter, $NB906$, on Subaru/Suprime-Cam, we investigated the number density Ly$\alpha$ emitters (LAE) around QSO at z=6.4. To date, this highest redshift observation, where LAEs luminous are investigated. Due large field-of-view Suprime-Cam, survey area $\sim$5400~cMpc$^2$, much larger than previously studies z=5.7 ($\sim$200 cMpc$^2$). In field,...
We present UV and Ly$\alpha$ radial surface brightness (SB) profiles of emitters (LAEs) at $z=2.84$ detected with the Hyper Suprime-Cam (HSC) on Subaru Telescope. The depth our data, together wide field coverage including a protocluster, enable us to study dependence halos (LAHs) various galaxy properties, Mpc-scale environments. images 3490 LAEs are extracted, stacking yields SB sensitivity $\sim1\times10^{-20}\mathrm{~erg~s^{-1}~cm^{-2}~arcsec^{-2}}$ in Ly$\alpha$, reaching expected level...
Abstract We present Atacama Large Millimeter/submillimeter Array [C ii ] 158 μ m line and underlying far-IR continuum emission observations (0.″57 × 0.″46 resolution) toward a quasar–quasar pair system recently discovered at z = 6.05. The quasar nuclei (C1 C2) are faint ( M 1450 ≳ −23 mag), but we detect very bright bridging the 12 kpc between two objects extending beyond them (total luminosity L ≃ 6 10 9 ⊙ ). ]-based total star formation rate of is ∼550 yr −1 (the IR-based dust-obscured...
We report on the results of deep and wide-field (1.1 deg$^2$) narrow-band observations with Subaru/Hyper Suprime-Cam (HSC) a field around hyperluminous QSO (HLQSO), HS1549+1919, residing in protocluster at $z=2.84$, to map large-scale structure Ly$\alpha$ emitters (LAEs). One HSC pointing enables us detect 3490 LAEs 76 extended blobs (LABs), probing diverse environments from voids protoclusters. The HLQSO is found be near center protocluster, which corresponds intersection $\sim$100...
Abstract Circumgalactic Ly α nebulae are gaseous halos around galaxies exhibiting luminous extended emission. This work investigates from deep imaging of ∼12 deg 2 sky, targeted by the MAMMOTH-Subaru survey. Utilizing wide-field capability Hyper Suprime-Cam, we present one largest blind nebula selections, including QSO nebulae, blobs, and radio galaxy down to typical σ surface brightness <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo...
Abstract We present infrared K ′-band (2.1 μ m) and L (3.8 high-spatial-resolution (<0.″3) imaging observations of 17 nearby ( z < 0.17) ultraluminous galaxies (ULIRGs) assisted with the adaptive optics Subaru Telescope. search for compact red ′ − color emission as indicator luminous active galactic nuclei (AGNs) due to AGN-heated hot dust emission. Two dual AGN candidates are revealed. Combining these results those our previous study, we can state that detected fraction AGNs in ULIRGs...