7 citations · 21 across the 22 of their papers we have counts for
24 papers
Can Blue UV-Bright Galaxies Drive Reionization at Cosmic Dawn? An Galaxy with at
Yunjing Wu, Sijia Cai, Yongda Zhu +28
We revisit EBG-1, a gravitationally lensed galaxy at , using newly obtained deep (14 hr) JWST/NIRSpec G235M () spectroscopy. EBG-1 is one of the bluest gala…
SN Helios: A Multiply Imaged Type II Supernova Opening Time-Delay Cosmography beyond redshift of 3
Seiji Fujimoto, Conor Larison, Justin D. R. Pierel +64
We report the discovery and spectroscopic confirmation of SN Helios, a strongly lensed, multiply imaged Type II supernova (SN) at behind the galaxy cluster RXC J0018.5+162…
A sub-100 pc view at z~5 of a Multiply-Imaged Massive Quiescent Galaxy
Richard Pan, Danilo Marchesini, Joseph F. V. Allingham +34
Recent James Webb Space Telescope spectroscopic surveys reveal an abundance of rapidly assembled early galaxies in the first billion years. Cosmological simulations struggle to rep…
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…
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…
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…
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…
Chemical Abundance Ratios of Nitrogen Rich Galaxies Identified at : Observational Demographics and Models
Kuria Watanabe, Masami Ouchi, Kimihiko Nakajima +13
We present chemical abundance ratios of 8 nitrogen-rich ([N/O]) galaxies at identified by the first 4 years of the JWST observations, and compare these ratios wi…
Back to Normal Again: Possible Destinies of JWST overmassive SMBHs and "Little Red Dots" in the View of Shin-Uchuu Simulation
Haojie Hu, Hiroto Yanagisawa, Moka Nishigaki +3
The James Webb Space Telescope (JWST) has enabled the discovery of hundreds of supermassive black holes (SMBHs) at redshifts . A non-negligible fraction of these SMBH…
VENUS: Strong-lensing model of MACS J1931.8-2635 -- revealing the farthest multiply imaged supernova
Joseph F. V. Allingham, Adi Zitrin, Vasily Kokorev +42
We present a parametric strong-lensing model for the galaxy cluster MACS J1931.8-2635 (), accompanying the detection of the spectroscopically confirmed SN Eos at $z = 5…
A spectroscopically confirmed, strongly lensed, metal-poor Type II supernova at z = 5.13
David A. Coulter, Conor Larison, Justin D. R. Pierel +88
Observing supernovae (SNe) in the early Universe (z > 3) provides a window into how both galaxies and individual stars have evolved over cosmic time, yet a detailed study of high-r…
VENUS: Two Faint Little Red Dots Separated by Hidden in a Single Lensed Galaxy at
Hiroto Yanagisawa, Masami Ouchi, Miriam Golubchik +47
We report the identification of a pair of faint little red dots (LRDs), dubbed Red Eyes, in a strongly-lensed galaxy at behind the PLCKG004.5-10.5 cluster, identified from…
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…
Little red dot variability over a century reveals black hole envelope via a giant Einstein cross
Zijian Zhang, Mingyu Li, Masamune Oguri +79
"Little red dots" (LRDs) represent a new population of astronomical objects uncovered by JWST whose nature remains debated. Although many LRDs are suspected as active galactic nucl…
VENUS: A Strongly Lensed Clumpy Galaxy at behind the Galaxy Cluster MACS J0257.1-2325
Minami Nakane, Vasily Kokorev, Seiji Fujimoto +75
We present the discovery of a strongly lensed galaxy at , dubbed the ``Misty Moons'', identified in the JWST Treasury Survey, Vast Exploration for Nascent, Unexplored S…
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…
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…
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…
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…
JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at z~7-14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe
Yuichi Harikane, Akio K. Inoue, Richard S. Ellis +33
We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at . Our sample is composed of 60 galaxies at $z_\mathrm{spec}…
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…
Dynamics of a Galaxy at z > 10 Explored by JWST Integral Field Spectroscopy: Hints of Rotating Disk Suggesting Weak Feedback
Yi Xu, Masami Ouchi, Hidenobu Yajima +9
We investigate the dynamics of GN-z11, a luminous galaxy at , carefully analyzing the public deep integral field spectroscopy (IFS) data taken with JWST NIRSpec IFU. While…
Balmer Decrement Anomalies in Galaxies at z ~ 6 Found by JWST Observations: Density-Bounded Nebulae or Excited H I Clouds?
Hiroto Yanagisawa, Masami Ouchi, Kimihiko Nakajima +11
We investigate the physical origins of the Balmer decrement anomalies in GS-NDG-9422 (Cameron et al. 2023) and RXCJ2248-ID (Topping et al. 2024) galaxies at whose $\mathr…