A5068839761- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Radio Frequency Integrated Circuit Design
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Astrophysics and Star Formation Studies
- Semiconductor Lasers and Optical Devices
- Adaptive optics and wavefront sensing
- Microwave Engineering and Waveguides
- Pulsars and Gravitational Waves Research
- High-pressure geophysics and materials
- Bluetooth and Wireless Communication Technologies
- Antenna Design and Optimization
- Cosmology and Gravitation Theories
The University of Tokyo
2024
Mitsubishi Group (Japan)
2005
Abstract We present the evolution of Ly α emission derived from 53 galaxies at z = 6.6–13.2, which have been identified by multiple JWST/NIRSpec spectroscopy programs Early Release Science, General Observer, Director's Discretionary Time, and Guaranteed Time Observations. These fall on star formation main sequence are typical star-forming with UV magnitudes −22.5 ≤ M −17.0. find that 15 out show >3 σ level, we obtain equivalent width (EW) measurements stringent 3 upper limits for 38...
Abstract We present the number densities and physical properties of bright galaxies spectroscopically confirmed at z ∼ 7–14. Our sample is composed 60 spec 7–14, including recently = 12.34–14.18 with JWST, as well new confirmations 6.583–7.643 −24 < M UV −21 mag using ALMA Keck. JWST/NIRSpec observations have also revealed that very galaxy candidates 10–13 identified from ground-based telescope images before JWST are passive 3–4, emphasizing necessity strict screening spectroscopy in...
Abstract We present the rest-frame optical and UV surface brightness (SB) profiles for 149 galaxies with Mopt &lt; −19.4 mag at z = 4–10 (29 of which are spectroscopically confirmed JWST NIRSpec), securing high signal-to-noise ratios 10–135 deep NIRCam 1–$5\, \mu$m images obtained by CEERS survey. derive morphologies our high-z galaxies, carefully evaluating systematics SB profile measurements Monte Carlo simulations as well impacts a) AGNs, b) multiple clumps including galaxy mergers,...
We present the statistical properties of Ly$\alpha$ emission in 586 galaxies at $z=4.5-14.2$, observed by multiple JWST/NIRSpec spectroscopy projects, including JADES, GLASS, CEERS, and GO/DDT programs. obtain equivalent width (EW), escape fraction, ionizing photon production efficiency measurements or upper limits for these galaxies, confirm that emitting galaxy fraction decreases towards higher redshifts. derive luminosity functions from $z\sim 5$ to 10-14$ with EW distributions UV...
We homogeneously investigate the morphological properties of $169$ galaxies at $z\sim10-16$ with deep JWST NIRCam images employing our established techniques GALFIT modeling and uncertainty evaluation (systematics+statistics). obtain effective radii $r_{\rm e}$ ranging $20-500$ pc, a distribution significantly broader than scatter made by uncertainties. find that is well described log-normal mean e}=133^{+13}_{-12}$ pc standard deviation $\sigma_{{\rm ln}r_{\rm e}} = 0.52 \pm 0.08$. The...
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 the number densities and physical properties of bright galaxies spectroscopically confirmed at $z\sim7-14$. Our sample is composed 53 $z_\mathrm{spec}\sim7-14$, including recently-confirmed $z_\mathrm{spec}=12.34-14.32$ with JWST, as well new confirmations $z_\mathrm{spec}=6.583-7.643$ $-24< M_\mathrm{UV}< -21$ mag using ALMA Keck. JWST/NIRSpec observations have also revealed that very galaxy candidates $z\sim10-13$ identified from ground-based telescope images before JWST are...
We present HeI/H$\beta$-flux and He/H-abundance ratios in three JWST galaxies with significant constraints on N/O-abundance ratios, GS-NDG-9422, RXCJ2248-ID, GLASS150008 at $z\sim 6$ mostly the spectroscopic coverage from HeI$\lambda$4471 HeII$\lambda$4686 to HeI$\lambda$7065, comparing 68 local-dwarf galaxies. find that these high-$z$ strong HeI emission HeI/H$\beta$ flux generally larger than those of derive He/H all detected HeI, HeII, $2-3$ hydrogen Balmer lines same manner as local...
Abstract We investigate the physical origins of Balmer decrement anomalies in GS-NDG-9422 and RXCJ2248-ID galaxies at z ∼ 6 whose H α /H β values are significantly smaller than 2.7, latter which also shows anomalous γ δ beyond errors. Because decrements not reproduced under Case B recombination, we explore nebulae with optical depths larger recombination by modeling. find two cases quantitatively explaining anomalies: (1) density-bounded that opaque only up to around Ly –Ly8 transitions (2)...
Abstract We present He i /H β flux and He/H abundance ratios in three James Webb Space Telescope galaxies with significant constraints on N/O ratios, GS-NDG-9422, RXCJ2248-ID, GLASS150008 at z ∼ 6 mostly the spectroscopic coverage from λ 4471 ii 4686 to 7065, comparing 68 local dwarf galaxies. find that these high- strong emission generally larger than those of derive all detected , 2−3 hydrogen Balmer lines same manner as determination conducted for cosmology studies. These show...
Abstract We investigate the dynamics of GN-z11, a luminous galaxy at z = 10.60, carefully analyzing public deep integral field spectroscopy (IFS) data taken with JWST NIRSpec unit. While observations IFS originally targeted an He ii clump near we find that C iii ] λ 1907, 1909 emission from ionized gas GN-z11 is bright and spatially extended significantly beyond point-spread function (PSF). The shows velocity gradient red- blueshifted components in north south directions, respectively, which...
We investigate the dynamics of GN-z11, a luminous galaxy at $z=10.60$, carefully analyzing public deep integral field spectroscopy (IFS) data taken with JWST NIRSpec IFU. While observations IFS originally targeted He II clump near we find that C III]$\lambda\lambda1907,1909$ emission from ionized gas GN-z11 is bright and spatially extended significantly beyond point-spread function (PSF) in contrast GN-z11's compact UV-continuum morphology. The III] shows velocity gradient, red- blue-shifted...
We present the evolution of Ly$\alpha$ emission derived from 53 galaxies at $z=6.6-13.2$ that are identified by multiple JWST/NIRSpec spectroscopy programs ERS, GO, DDT, and GTO. These fall on star-formation main sequence typical star-forming with UV magnitudes $-22.5\leq M_\mathrm{UV}\leq-17.0$. find 15 out show $>3\sigma$ levels, obtain equivalent width (EW) measurements stringent $3\sigma$ upper limits for 38 galaxies, respectively. Confirming velocity offsets line widths our comparable...
This paper describes a wide-band voltage controlled oscillator (VCO) with the triple oscillation bandwidth and better flatness of phase noise in using varactor-tuned circuits. Altering capacitances varactor diodes connected to every ports HBT same direction, more than 1.5 octaves has been obtained. A fabricated VCO employing triple-tuned circuits GaAs covered 1.56 achieving -114.9 dBc/Hz /spl plusmn/2.9 dB at 1 MHz offset from carrier output power 3.4dBm plusmn/2 C-Ku band.
Using the Subaru/FOCAS IFU capability, we examine spatially resolved relationships between gas-phase metallicity, stellar mass, and star-formation rate surface densities (Sigma_* Sigma_SFR, respectively) in extremely metal-poor galaxies (EMPGs) local universe. Our analysis includes 24 EMPGs, comprising 9,177 spaxels, which span a unique parameter space of metallicity (12+log(O/H) = 6.9 to 7.9) mass density ~ 10^5 10^7 Msun/kpc^2), extending beyond range existing large integral-field...
We investigate the physical origins of Balmer decrement anomalies in GS-NDG-9422 (Cameron et al. 2023) and RXCJ2248-ID (Topping 2024) galaxies at $z\sim 6$ whose $\mathrm{H}\alpha/\mathrm{H}\beta$ values are significantly smaller than $2.7$, latter which also shows anomalous $\mathrm{H}\gamma/\mathrm{H}\beta$ $\mathrm{H}\delta/\mathrm{H}\beta$ beyond errors. Because decrements not reproduced under Case B recombination, we explore nebulae with optical depths larger recombination by modeling....
We present an [O/Fe] ratio of a luminous galaxy GN-z11 at $z=10.60$ derived with the deep public JWST/NIRSpec data. fit medium-resolution grating (G140M, G235M, and G395M) data model spectra consisting BPASS-stellar CLOUDY-nebular in rest-frame UV wavelength ranges Fe absorption lines, carefully masking out other emission lines same manner as previous studies conducted for lower redshift ($z\sim 2-6$) galaxies oxygen abundance measurements. obtain Fe-rich...
Abstract We present an [O/Fe] ratio of a luminous galaxy GN-z11 at z = 10.60 derived with the deep public JWST/NIRSpec data. fit medium-resolution grating (G140M, G235M, and G395M) data model spectra consisting BPASS-stellar Cloudy -nebular in rest-frame UV wavelength ranges Fe absorption lines, carefully masking other emission lines same manner as previous studies conducted for lower-redshift ( ∼ 2–6) galaxies oxygen abundance measurements. obtain Fe-rich <mml:math...
We present the luminosity functions (LFs) and angular correlation (ACFs) derived from 18,960 Ly$\alpha$ emitters (LAEs) at $z=2.2-7.3$ over a wide survey area of $\lesssim24 {\rm deg^2}$ that are identified in narrowband data Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) Cosmic HydrOgen Reionization Unveiled with (CHORUS) surveys. Confirming large sample 241 spectroscopically LAEs, we determine LFs ACFs brighter range down to $0.5L_{\star}$, confirm our measurements consistent...
We investigate UV continuum slopes $\beta$ of 974 galaxies at $z=4-14$ using archival JWST/NIRSpec PRISM spectra obtained from major JWST GTO, ERS, and GO programs, including JADES, CEERS, UNCOVER. Among these galaxies, we identify a remarkable galaxy $z=9.25$, dubbed EBG-1, with significantly blue slope $\beta=-2.99\pm0.15$, unlike the rest that exhibit red continua or ambiguous hindered by large uncertainties. confirm value negligibly changes data reduction fitting wavelength ranges for...
We present the rest-frame optical and UV surface brightness (SB) profiles for $149$ galaxies with $M_{\rm opt}< -19.4$ mag at $z=4$-$10$ ($29$ of which are spectroscopically confirmed JWST NIRSpec), securing high signal-to-noise ratios $10$-$135$ deep NIRCam $1$-$5\mu$m images obtained by CEERS survey. derive morphologies our high-$z$ galaxies, carefully evaluating systematics SB profile measurements Monte Carlo simulations as well impacts a) AGNs, b) multiple clumps including galaxy...