201 citations · 2.1k across the 98 of their papers we have counts for
98 papers
A new clump-based star formation model for galaxy simulations: implications for high-redshift compact star clusters
Shu Horie, Hidenobu Yajima
We develop a new star formation model for galaxy simulations in which star-forming gas clumps are identified on-the-fly and converted into stars with an efficiency set…
Diversity of Ionized Gas Structures in Nearby Metal-poor Dwarf Galaxies
Yuki Takagishi, Takuya Hashimoto, Kazuya Matsubayashi +13
We investigate whether optical and far-infrared [O III] emission from nearby metal-poor dwarf galaxies can be represented by a homogeneous one-zone ionized-gas model with a single…
RIOJA. Environmental Effects on Stellar Populations and Ionized Gas in a Protocluster at
Wataru Osone, Takuya Hashimoto, Javier Álvarez-Márquez +23
Protoclusters in the epoch of reionization provide key laboratories for investigating how environment shapes early galaxy formation and evolution, and may also have contributed to…
Gas-Phase Metallicity and Nitrogen Abundances in Low-Mass Galaxies Down to at -- from JWST Lensing Cluster Surveys
Hiroya Umeda, Masami Ouchi, Kimihiko Nakajima +7
We analyze 405 deep JWST/NIRSpec spectra of star-forming galaxies at -- from DREAMS and other lensing-cluster surveys to study chemical enrichment in intrinsically fai…
DREAMS. JWST Spectroscopy of a Galaxy with an ALMA Dust Continuum Detection: Early Dust, Very High , and a Multi-wavelength [OIII] Ratio Discrepancy
Kana Takechi, Masami Ouchi, Kimihiko Nakajima +10
We present a deep DREAMS JWST/NIRSpec MSA medium-grating spectrum of MACS0416-Y1, a galaxy at with the highest-redshift ALMA dust continuum detection to date, in order to…
Double-Peaked Ly Emission during Reionization Requires Nearby Voids and a Favorable Local Ionizing Background
Hyunbae Park, Aaron Smith, Intae Jung +11
Several Lyman-alpha (Ly) emitters deep into the reionization era exhibit double-peaked Ly emission profiles, raising the question of how the intergalactic medium can transmit…
ATT12: The Antarctic 12-m Terahertz Telescope for Studies of Dusty Galaxies. I. Instrument Sensitivity and Science Forecasts
Koki Wakasugi, Takuya Hashimoto, Nario Kuno +13
We present a feasibility study of the Antarctic 12m Terahertz Telescope (ATT12), a next-generation facility to be constructed at New Dome Fuji in Antarctica, designed to open up th…
JWST Spectroscopic Census of ALMA Faint Submillimeter Galaxies in the Hubble Ultra Deep Field
Tomokazu Kiyota, Masami Ouchi, Daisuke Iono +6
We present a JWST/NIRSpec rest-frame optical spectroscopic census of ALMA 1-mm continuum sources in the Hubble Ultra Deep Field (UDF) identified by the deep ALMA UDF and ASPECS pro…
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…
Formation of Substructure in Luminous Submillimeter Galaxies (FOSSILS): Evidence of Multiple Pathways to Trigger Starbursts in Luminous Submillimeter Galaxies
Ryota Ikeda, Daisuke Iono, Ken-ichi Tadaki +19
We present an analysis of rest-frame optical and far-infrared continuum emission in three luminous submillimeter galaxies (SMGs) at . The SMGs are spatial…
Formation of over-massive black holes in high-redshift disk galaxies via globular cluster accretion
Hidenobu Yajima
Recent observations with the James Webb Space Telescope (JWST) have suggested the existence of over-massive black holes (OMBHs) in high-redshift galaxies. In this paper, we propose…
Submillimeter galaxy overdensities around physically associated quasar pairs
Eileen Herwig, Fabrizio Arrigoni Battaia, Chian-Chou Chen +4
A commonly employed method to detect protoclusters in the young universe is the search for overdensities of massive star forming galaxies, such as submillimeter galaxies (SMGs), ar…
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…
FOREVER22: Insights into star formation and clustering properties of protoclusters from simulations and JWST
Kana Morokuma-Matsui, Hidenobu Yajima, Makito Abe
Using cosmological hydrodynamic simulations with radiative transfer, we investigate star formation and overdensity () in Coma-type cluster progenitors from to 6. Our simu…
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…
Bridging Theory and Observations: Insights into Star Formation Efficiency and Dust Attenuation in Galaxies
Daisuke Toyouchi, Hidenobu Yajima, Andrea Ferrara +1
We investigate early galaxy evolution by modeling self-consistently their radially-resolved evolution of gas, stars, heavy elements, and dust content. Our model successfully reprod…
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…
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…
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…
A Galaxy with an Extremely Blue UV Slope at Identified by JWST Spectroscopy: Evidence for a Weak Nebular Continuum and Efficient Ionizing Photon Escape?
Hiroto Yanagisawa, Masami Ouchi, Kimihiko Nakajima +8
We investigate UV continuum slopes of 863 galaxies at using archival JWST/NIRSpec PRISM spectra obtained from major JWST GTO, ERS, and GO programs, including JADES, CE…
Impact of Ly radiation force on super-Eddington accretion onto a massive black hole
Takuya Mushano, Takumi Ogawa, Ken Ohsuga +2
The viability of super-Eddington accretion remains a topic of intense debate, crucial for understanding the formation of supermassive black holes in the early universe. However, th…
Constraining Reionization with Lyα Damping-Wing Absorption in Galaxy Spectra: A Machine Learning Model Based on Reionization Simulations
Hyunbae Park, Intae Jung, Hidenobu Yajima +8
Recently, NIRSpec PRISM/CLEAR observations by JWST have begun providing rest-frame UV continuum measurements of galaxies at , revealing signatures of Ly damping-wing…
Detection of the [O I] 63 m emission line from the quasar J2054-0005
Nozomi Ishii, Takuya Hashimoto, Carl Ferkinhoff +23
We report the highest-redshift detection of [O I] 63 m from a luminous quasar, J2054-0005, at based on the Atacama Large Millimeter/sub-millimeter Array Band 9 observat…
Strong He I Emission Lines in High N/O Galaxies at Identified in JWST Spectra: High He/H Abundance Ratios or High Electron Densities?
Hiroto Yanagisawa, Masami Ouchi, Kuria Watanabe +14
We present HeI/H-flux and He/H-abundance ratios in three JWST galaxies with significant constraints on N/O-abundance ratios, GS-NDG-9422, RXCJ2248-ID, and GLASS150008 at $z\sim…