activity
20092026
most citedA Comprehensive Study on Galaxies at z~9-16 Found in the Early JWST Data: UV Luminosity Functions and Cosmic Star-Formation History at the Pre-Reionization Epoch

533 citations · 6.6k across the 107 of their papers we have counts for

collaborators
Showing 2025Show all

10 papers · 1 filter

astro-ph.GA2025

DREAMS.II. Galaxy Demographics from Direct Te-Based Metallicities at z~2-10: Tracing the Evolution of the Mass-Metallicity and Fundamental Relations

Moka Nishigaki, Kimihiko Nakajima, Masami Ouchi +6

We present the statistics of line ratios and direct Te-based metallicities from JWST medium-resolution spectra of 292 galaxies at z=2-10, combining DREAMS observations with those o…

astro-ph.GA2025

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…

astro-ph.GA2025

An Ultra-Faint, Chemically Primitive Galaxy Forming in the Reionization Era

Kimihiko Nakajima, Masami Ouchi, Yuichi Harikane +9

The formation of the first stars and galaxies marked the onset of chemical enrichment, yet direct observations of such primordial systems remain elusive. Here we present James Webb…

astro-ph.GA2025★ 2 cited

JWST & ALMA Joint Analysis with [OII]3726,3729, [OIII]4363, [OIII]88m, and [OIII]52m: Multi-Zone Evolution of Electron Densities at and Its Impact on Metallicity Measurements

Yuichi Harikane, Ryan L. Sanders, Richard Ellis +8

We present a JWST and ALMA detailed study of the ISM properties of high-redshift galaxies. Our JWST/NIRSpec IFU spectroscopy targeting three galaxies at detects key rest-fr…

astro-ph.GA2025

Probing the Cosmic Reionization History with JWST: Gunn-Peterson and Ly Damping Wing Absorption at

Hiroya Umeda, Masami Ouchi, Yuta Kageura +4

We present a statistical analysis of Ly absorption using 581 galaxies at --13 observed with multiple JWST/NIRSpec spectroscopy programs, including JADES, UNCOVER, CEERS,…

astro-ph.GA2025★ 1 cited

Comprehensive JWST+ALMA Study on the Extended Ly Emitters, Himiko and CR7 at : Blue Major Merger Systems in Stark Contrast to Submillimeter Galaxies

Tomokazu Kiyota, Masami Ouchi, Yi Xu +14

We present various properties of two bright extended Ly objects, Himiko and CR7, at thoroughly investigated with JWST/NIRCam photometry, NIRSpec-IFU spectroscopy, and AL…

astro-ph.GA2025

ChemicalUniverseMachine I: Uncovering the Cosmic Evolution of Metals in the Galaxy-ISM-CGM Ecosystem

Moka Nishigaki, Peter Behroozi, Masami Ouchi +5

We present an empirical chemical evolution model that explains the distribution of metals in the interstellar medium (ISM) and the circumgalactic medium (CGM) of galaxies based on…

astro-ph.GA2025★ 1 cited

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…

astro-ph.GA2025★ 1 cited

Morphological Demographics of Galaxies at : Log-Normal Size Distribution and Exponential Profiles Consistent with the Disk Formation Scenario

Yoshiaki Ono, Masami Ouchi, Yuichi Harikane +5

We homogeneously investigate the morphological properties of galaxies at with deep JWST NIRCam images employing our established techniques of GALFIT modeling and…

astro-ph.GA2025★ 2 cited

Census of Ly Emission from Galaxies at : Evolution of the Ly Luminosity Function and a Late Sharp Cosmic Reionization

Yuta Kageura, Masami Ouchi, Minami Nakane +6

We present the statistical properties of Ly emission in 586 galaxies at , observed by multiple JWST/NIRSpec spectroscopy projects, including JADES, GLASS, CEERS, and…