533 citations · 1.5k across the 46 of their papers we have counts for
47 papers
DREAMS: Taking the Temperature of a Massive Galaxy at z ~ 11
L. Parente, E. Vanzella, M. Messa +15
We present a detailed photometric and spectroscopic analysis of Janus-11, a galaxy magnified by a factor 1.6 by the galaxy cluster MACS J0416. It was observ…
Gas-Phase Metallicity and Nitrogen Abundances in Low-Mass Galaxies Down to at -- from JWST Lensing Cluster Surveys
Hiroya Umeda, Masami Ouchi, Kimihiko Nakajima +7
We analyze 405 deep JWST/NIRSpec spectra of star-forming galaxies at -- from DREAMS and other lensing-cluster surveys to study chemical enrichment in intrinsically fai…
The Mysterious Case of Iron in XMPs: Anomalous High log(Fe/O) Observed in Extremely Metal-Poor Galaxies HSCJ1631+4426 and SDSSJ0811+4730
Aaron Myszka, Themiya Nanayakkara, Karl Glazebrook +8
We present integral field spectroscopic observations of two local extremely metal-poor galaxies (XMPs), HSCJ1631+4426 and SDSSJ0811+4730, obtained with the Keck Cosmic Web Imager (…
A UV-Luminous Galaxy at z=11 with Surprisingly Weak Star Formation Activity
Yuichi Harikane, Pablo G. Perez-Gonzalez, Javier Alvarez-Marquez +8
One of the major discoveries by the James Webb Space Telescope (JWST) is the identification of a large population of luminous galaxies at , challenging theoretical models for…
EMPRESS. XV. A New Determination of the Primordial Helium Abundance Suggesting a Moderately Low Value
Hiroto Yanagisawa, Masami Ouchi, Akinori Matsumoto +18
We present a new constraint on the primordial helium abundance, , based on Subaru observations. A major source of uncertainty in previous determination…
Fe Abundances of Early Galaxies at Derived with Deep JWST Spectra
Minami Nakane, Masami Ouchi, Kimihiko Nakajima +12
We derive Fe-abundance ratios of 7 galaxies at with whose JWST/NIRSpec spectra achieve very high signal-to-noise ratios, , a…
EMPRESS. X. Spatially resolved mass-metallicity relation in extremely metal-poor galaxies: evidence of episodic star-formation fueled by a metal-poor gas infall
Kimihiko Nakajima, Masami Ouchi, Yuki Isobe +47
Using the Subaru/FOCAS IFU capability, we examine the spatially resolved relationships between gas-phase metallicity, stellar mass, and star-formation rate surface densities (Sigma…
The Physical Origin of Extreme Emission Line Galaxies at High redshifts: Strong {\sc [Oiii]} Emission Lines Produced by Obscured AGNs
Chenghao Zhu, Yuichi Harikane, Masami Ouchi +21
We present deep Subaru/FOCAS spectra for two extreme emission line galaxies (EELGs) at with strong {\sc[Oiii]}5007 emission lines, exhibiting equivalent widths (EWs) o…
Low [O/Fe] Ratio in a Luminous Galaxy at the Early Cosmic Epoch (): Signature of Short Delay Time or Bright Hypernovae/Pair-Instability Supernovae?
Minami Nakane, Masami Ouchi, Kimihiko Nakajima +12
We present an [O/Fe] ratio of a luminous galaxy GN-z11 at derived with the deep public JWST/NIRSpec data. We fit the medium-resolution grating (G140M, G235M, and G395M) d…
JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at z~7-14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe
Yuichi Harikane, Akio K. Inoue, Richard S. Ellis +33
We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at . Our sample is composed of 60 galaxies at $z_\mathrm{spec}…
Strong He I Emission Lines in High N/O Galaxies at Identified in JWST Spectra: High He/H Abundance Ratios or High Electron Densities?
Hiroto Yanagisawa, Masami Ouchi, Kuria Watanabe +14
We present HeI/H-flux and He/H-abundance ratios in three JWST galaxies with significant constraints on N/O-abundance ratios, GS-NDG-9422, RXCJ2248-ID, and GLASS150008 at $z\sim…
Dynamics of a Galaxy at z > 10 Explored by JWST Integral Field Spectroscopy: Hints of Rotating Disk Suggesting Weak Feedback
Yi Xu, Masami Ouchi, Hidenobu Yajima +9
We investigate the dynamics of GN-z11, a luminous galaxy at , carefully analyzing the public deep integral field spectroscopy (IFS) data taken with JWST NIRSpec IFU. While…
Balmer Decrement Anomalies in Galaxies at z ~ 6 Found by JWST Observations: Density-Bounded Nebulae or Excited H I Clouds?
Hiroto Yanagisawa, Masami Ouchi, Kimihiko Nakajima +11
We investigate the physical origins of the Balmer decrement anomalies in GS-NDG-9422 (Cameron et al. 2023) and RXCJ2248-ID (Topping et al. 2024) galaxies at whose $\mathr…
Probing Chemical Enrichment in Extremely Metal-Poor Galaxies
Keita Fukushima, Kentaro Nagamine, Akinori Matsumoto +4
The chemical composition of galaxies offers vital insights into their formation and evolution. In particular, the relationship between helium abundance (He/H) and metallicity serve…
Ly Emission at : Clear Ly Equivalent Width Evolution Indicating the Late Cosmic Reionization History
Minami Nakane, Masami Ouchi, Kimihiko Nakajima +6
We present the evolution of Ly emission derived from 53 galaxies at that are identified by multiple JWST/NIRSpec spectroscopy programs of ERS, GO, DDT, and GTO. The…
Stellar- and AGN-Driven Outflows in JWST Galaxies at z=3-9: More Frequent, Wider Opening Angles, and Mostly Bounded
Yi Xu, Masami Ouchi, Kimihiko Nakajima +5
We study outflows in 130 galaxies with -22<MUV<-16 at z=3-9 identified in JWST NIRSpec and NIRCam WFSS data taken by the ERO, CEERS, FRESCO, GLASS, and JADES programs. We identify…
Census for the Rest-frame Optical and UV Morphologies of Galaxies at : First Phase of Inside-Out Galaxy Formation
Yoshiaki Ono, Yuichi Harikane, Masami Ouchi +7
We present the rest-frame optical and UV surface brightness (SB) profiles for galaxies with mag at - ( of which are spectroscopically confir…
JWST Identification of Extremely Low C/N Galaxies with [N/O] at Evidencing the Early CNO-Cycle Enrichment and a Connection with Globular Cluster Formation
Yuki Isobe, Masami Ouchi, Nozomu Tominaga +9
We present chemical abundance ratios of 70 star-forming galaxies at -10 observed by the JWST/NIRSpec ERO, GLASS, and CEERS programs. Among the 70 galaxies, we have pinpoint…
Statistics for Galaxy Outflows at with Imaging and Spectroscopic Signatures Identified with JWST/NIRCam and NIRSpec Data
Yechi Zhang, Masami Ouchi, Kimihiko Nakajima +5
We present statistics of galaxy outflows indicated by spatially-extended gas emission and broad lines. With a total of 61 spectroscopically confirmed galaxies at $z\sim…
JWST Measurements of Neutral Hydrogen Fractions and Ionized Bubble Sizes at Obtained with Ly Damping Wing Absorptions in 27 Bright Continuum Galaxies
Hiroya Umeda, Masami Ouchi, Kimihiko Nakajima +5
We present volume-averaged neutral hydrogen fractions $x_{\rm \HI}$ and ionized bubble radii measured with Ly damping wing absorption of galaxies at the epoch of rei…
EMPRESS. XIV. Strong High Ionization Lines of Young Galaxies at : Ionizing Spectra Consistent with the Intermediate Mass Black Holes with
Shun Hatano, Masami Ouchi, Hiroya Umeda +16
We present ionizing spectra estimated at 13.6--100 eV for ten dwarf galaxies with strong high ionization lines of He {\sc {ii}}4686 and [Ne {\sc{v}}]3426 ([Ne {\sc{iv}}]24…
EMPRESS. XIII. Chemical Enrichments of Young Galaxies Near and Far at z ~ 0 and 4-10: Fe/O, Ar/O, S/O, and N/O Measurements with Chemical Evolution Model Comparisons
Kuria Watanabe, Masami Ouchi, Kimihiko Nakajima +14
We present gas-phase elemental abundance ratios of 7 local extremely metal-poor galaxies (EMPGs) including our new Keck/LRIS spectroscopy determinations together with 33 JWST $z\si…
Pure Spectroscopic Constraints on UV Luminosity Functions and Cosmic Star Formation History From 25 Galaxies at Confirmed with JWST/NIRSpec
Yuichi Harikane, Kimihiko Nakajima, Masami Ouchi +5
We present pure spectroscopic constraints on the UV luminosity functions and cosmic star formation rate (SFR) densities from 25 galaxies at . By reducin…
Near-infrared Variability Detected in the Young Star-Forming Dwarf Galaxy SBS 0335-052E
Shun Hatano, Mitsuru Kokubo, Masami Ouchi +17
SBS~0335-052E is a young star-forming dwarf galaxy with a total stellar mass of and an extremely low metallicity (), which…