activity
20242026
collaborators

7 papers

astro-ph.GA2026

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.GA2026

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…

astro-ph.GA2025

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…

astro-ph.GA2025

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…

astro-ph.GA2025

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)…

astro-ph.GA2024

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…