19 citations · 25 across the 11 of their papers we have counts for
13 papers
SIRIUS Project: Dynamical Evolution of Primordial Binaries during Star Cluster Formation
Naoto Harada, Michiko S. Fujii, Takayuki R. Saitoh +1
Binary populations are closely linked to the star formation process; however, their primordial properties can be changed by subsequent dynamical interactions within their natal clu…
SIRIUS: The relation between the diversity of dwarf galaxies and their formation histories
Chi-Hong Lin, Michiko S Fujii, Takayuki R Saitoh +1
Low-mass dwarf galaxies () are fundamental cosmological building blocks, yet the physical processes driving their structural diversity remain…
SIRIUS: Dark matter cusp evolution in dense dwarf galaxies
Katsuhiro Kaneko, Takayuki R. Saitoh, Yutaka Hirai +1
Dwarf galaxies have a wide variety of structures, such as dark matter (DM) distribution, stellar-to-halo mass ratio, and stellar density. Recent high-resolution simulations have sh…
Nitrogen enhancement of GN-z11 by metal pollution from supermassive stars
Sho Ebihara, Michiko S. Fujii, Takayuki R. Saitoh +4
Spectroscopic observations by the James Webb Space Telescope (JWST) have revealed young, compact, high-redshift () galaxies with high nitrogen-to-oxygen (N/O) ratios. GN-z11 at…
Bursty star formation, chemical enrichment, and star cluster formation in numerical analogues of GN-z11
Takayuki R. Saitoh, Yutaka Hirai, Michiko S. Fujii +1
The James Webb Space Telescope reveals anomalous nitrogen enrichment (high N/O ratios) in compact, star-forming galaxies, such as GN-z11 at . The origin of this chemical s…
A New Subclass of Carbon-Enhanced Metal-Poor Stars at Extremely Low Metallicity
Young Sun Lee, Timothy C. Beers, Yutaka Hirai +4
We report the discovery of a new subclass of carbon-enhanced metal-poor (CEMP) stars, characterized by high absolute carbon abundances (A(C) > 7.39) and extremely low metallicity (…
Deciphering the Milky Way's star formation at cosmic noon with high proper-motion stars: A precursor to the merger-driven starburst
Deokkeun An, Young Sun Lee, Yutaka Hirai +1
Evidence suggests that the Milky Way (MW) underwent a major collision with the Gaia-Sausage/Enceladus (GSE) dwarf galaxy around cosmic noon. While GSE has since been fully disrupte…
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…
SIRIUS: Identifying Metal-poor Stars Enriched by a Single Supernova in a Dwarf Galaxy Cosmological Zoom-in Simulation Resolving Individual Massive Stars
Yutaka Hirai, Takayuki R. Saitoh, Michiko S. Fujii +2
Metal-poor stars enriched by a single supernova (mono-enriched stars) are direct proof (and provide valuable probes) of supernova nucleosynthesis. Photometric and spectroscopic obs…
The -Process Alliance: Enrichment of -process Elements in a Simulated Milky Way-like Galaxy
Yutaka Hirai, Timothy C. Beers, Young Sun Lee +11
We study the formation of stars with varying amounts of heavy elements synthesized by the rapid neutron-capture process (-process) based on our detailed cosmological zoom-in sim…
Chemo-dynamical Evolution of Simulated Satellites for a Milky Way-like Galaxy
Yutaka Hirai, Evan N. Kirby, Masashi Chiba +5
The chemical abundances of Milky Way's satellites reflect their star formation histories (SFHs), yet, due to the difficulty of determining the ages of old stars, the SFHs of most s…
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…
Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys
Jihye Hong, Timothy C. Beers, Young Sun Lee +15
Photometric stellar surveys now cover a large fraction of the sky, probe to fainter magnitudes than large-scale spectroscopic surveys, and are relatively free from the target-selec…