842 citations · 3.5k across the 66 of their papers we have counts for
66 papers
Revealing α-Element's Past with Subaru/IRD: Oxygen Abundance of 35 Very Metal-Poor Stars from Near-IR OH lines
Bakuh Danang Setyo Budi, Wako Aoki, Nicholas Storm +10
Oxygen abundances in very and extremely metal-poor (V/EMP) stars provide critical constraints on early massive stars' nucleosynthesis. An Oxygen abundance analysis is presented for…
Potassium abundances in extremely metal poor stars: Implications for nucleosynthesis in the final stages of massive star evolution
M. N. Ishigaki, N. Tominaga, W. Aoki +5
We present a potassium (K) abundance analysis in extremely metal-poor (EMP) stars based on high-resolution () spectra obtained with the High Dispersion Spectrograph on…
Chemical abundances of seven stars in the GD-1 stream
Jing-Kun Zhao, Guang-Wei Li, Wako Aoki +13
We present the first detailed chemical abundances for seven GD-1 stream stars from Subaru/HDS spectroscopy. Atmospheric parameters were derived via color calibrations (…
Th/Eu abundance ratio of red giants in the Kepler Field
Ainun Azhari, Tadafumi Matsuno, Wako Aoki +2
The r-process production in the early universe has been well constrained by the extensive studies of metal-poor stars. However, the r-process enrichment in the metal-rich regime is…
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…
A Pristine View of Galactic Globular Clusters and their Peripheries: Omega Centauri
P. B. Kuzma, M. N. Ishigaki
The central regions of the globular cluster Omega Centauri ( Cen) have been extensively studied, but its outer regions and tidal structure have been less so. Gaia's astrometry u…
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…
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…
Four-hundred Very Metal-poor Stars Studied with LAMOST and Subaru. III. Dynamically Tagged Groups and Chemodynamical Properties
Ruizhi Zhang, Tadafumi Matsuno, Haining Li +9
Very metal-poor (VMP) stars record the signatures of early accreted galaxies, making them essential tools for unraveling the early stages of Galaxy formation. Understanding the ori…
Detection of a Spatially Extended Stellar Population in M33: A Shallow Stellar Halo?
Itsuki Ogami, Yutaka Komiyama, Masashi Chiba +8
We analyze the outer regions of M33, beyond 15 kpc in projected distance from its center using Subaru/HSC multi-color imaging. We identify Red Giant Branch (RGB) stars and Red Clum…
The structure of the stellar halo of the Andromeda galaxy explored with the NB515 for Subaru/HSC. I.: New Insights on the stellar halo up to 120 kpc
Itsuki Ogami, Mikito Tanaka, Yutaka Komiyama +16
We analyse the M31 halo and its substructure within a projected radius of 120 kpc using a combination of Subaru/HSC and CFHT/MegaCam - \& -…
Final Results of Search for New Milky Way Satellites in the Hyper Suprime-Cam Subaru Strategic Program Survey: Discovery of Two More Candidates
Daisuke Homma, Masashi Chiba, Yutaka Komiyama +11
We present the final results of our search for new Milky Way (MW) satellites using the data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP) survey over …
Transition probabilities of near-infrared Ce III lines from stellar spectra: applications to kilonovae
Nanae Domoto, Jae-Joon Lee, Masaomi Tanaka +6
Kilonova spectra provide us with information of r-process nucleosynthesis in neutron star mergers. However, it is still challenging to identify individual elements in the spectra m…
Cerium features in kilonova near-infrared spectra: implication from a chemically peculiar star
Masaomi Tanaka, Nanae Domoto, Wako Aoki +14
Observations of the kilonova from a neutron star merger event GW170817 opened a way to directly study r-process nucleosynthesis by neutron star mergers. It is, however, challenging…
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…
Machine learning detects multiplicity of the first stars in stellar archaeology data
Tilman Hartwig, Miho N. Ishigaki, Chiaki Kobayashi +2
In unveiling the nature of the first stars, the main astronomical clue is the elemental compositions of the second generation of stars, observed as extremely metal-poor (EMP) stars…
Existence of Tidal Tails for the Globular Cluster NGC 5824
Yong Yang, Jing-Kun Zhao, Miho N. Ishigaki +5
Context. Several dynamically cold streams have been associated with certain globular clusters (GCs) based on orbital energies and angular momenta. Some of these streams are surpris…
Revisit NGC 5466 Tidal Stream with , SDSS/SEGUE and LAMOST
Yong Yang, Jing-Kun Zhao, Miho N. Ishigaki +5
By mining the data from EDR3, SDSS/SEGUE DR16 and LAMOST DR8, 11 member stars of the NGC 5466 tidal stream are detected and 7 of them are newly identified. To reject contami…
Four-hundred Very Metal-Poor Stars Studied with LAMOST and Subaru. II. Elemental abundances
Haining Li, Wako Aoki, Tadafumi Matsuno +9
We present homogeneous abundance analysis of over 20 elements for 385 very metal-poor (VMP) stars based on the LAMOST survey and follow-up observations with the Subaru Telescope. I…
Four-hundred Very Metal-poor Stars studied with LAMOST and Subaru. I. Survey Design, Follow-up Program, and Binary Frequency
Wako Aoki, Haining Li, Tadafumi Matsuno +11
The chemical abundances of very metal-poor stars provide important constraints on the nucleosynthesis of the first generation of stars and early chemical evolution of the Galaxy. W…
High-precision chemical abundances of Galactic building blocks. II. Revisiting the chemical distinctness of the Helmi streams
Tadafumi Matsuno, Emma Dodd, Helmer H. Koppelman +6
Context: The Helmi streams are a kinematic substructure whose progenitor is likely a dwarf galaxy. Although 20 years have passed since their discovery, it is still unclear whether…
Top-heavy stellar mass distribution in galactic nuclei inferred from the universally high abundance ratio of [Fe/Mg]
Daisuke Toyouchi, Kohei Inayoshi, Miho N. Ishigaki +1
Recent observations of active galactic nuclei (AGNs) have shown a high Fe~II/Mg~II line-flux ratio in their broad-line regions, nearly independent of redshift up to .…
High-precision chemical abundances of Galactic building blocks. The distinct chemical abundance sequence of Sequoia
Tadafumi Matsuno, Helmer H. Koppelman, Amina Helmi +5
Context: Sequoia is a retrograde kinematic substructure in the nearby Galactic halo, whose properties are a matter of debate. For example, previous studies do not necessarily agree…
Origin of metals in old Milky Way halo stars based on GALAH and Gaia
Miho N. Ishigaki, Tilman Hartwig, Yuta Tarumi +6
Stellar and supernova nucleosynthesis in the first few billion years of the cosmic history have set the scene for early structure formation in the Universe, while little is known a…