activity
20242026
collaborators

8 papers

astro-ph.GA2026

ATLAS. IV. A JWST+MUSE Demographic Study of Ly Profiles in Little Red Dots

Yuta Kageura, Masami Ouchi, Hiroto Yanagisawa +6

We present an initial demographic study of Ly profiles in little red dots (LRDs) at --9 using --4000 spectroscopy. Our sample consists of 8 LRDs observed in the…

astro-ph.GA2026

ATLAS. III. Dust Around Little Red Dots: Hydrogen Line Ratios beyond Dust-free Non-Case B Models

Tomokazu Kiyota, Masami Ouchi, Hiroto Yanagisawa +7

We investigate broad hydrogen line ratios in little red dots (LRDs) using five high-redshift () sources from JWST/NIRSpec medium/high-resolution spectra in the DAWN JWST Archi…

astro-ph.GA2026

ATLAS. II. Extremely High Incidence of Balmer Line Absorption with Predominant Blueshifts in LRDs: Statistical Insights through Comparison with Type 1 AGNs

Hiroto Yanagisawa, Masami Ouchi, Tomokazu Kiyota +6

We present the statistical properties of H and H line absorption in little red dots (LRDs) at --7.2 using archival JWST/NIRSpec spectra from the DAWN JWST Archive…

astro-ph.GA2026

ATLAS. I. A Scaling Relation of LRDs between Broad H and Bolometric Luminosities: Enhanced Broad H Emission Relative to Low- Type 1 AGN

Hiroto Yanagisawa, Masami Ouchi, Tomokazu Kiyota +6

We investigate the demography of little red dots (LRDs) using 37 objects at - with JWST/NIRSpec PRISM and grating spectra compiled from various JWST programs. We focus o…

astro-ph.CO2026

A New Constraint on the Optical Depth from the Reionization History Independent of CMB Large-Scale E-Mode Polarization

Yuta Kageura, Masami Ouchi, Fumihiro Naokawa +5

Recent studies report a mild discrepancy between BAO and CMB measurements within the CDM framework. This discrepancy could be explained if the optical depth inferred from th…

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,…