201 citations · 2.1k across the 98 of their papers we have counts for
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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…
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…
Exploring the cosmic dawn and epoch of reionization with 21cm line
Hayato Shimabukuro, Kenji Hasegawa, Akira Kuchinomachi +2
The dark age of the universe, when no luminous object had existed, ended with the birth of the first stars, galaxies, and blackholes. This epoch is called cosmic dawn. Cosmic reion…
Detectability of 21cm-signal during the Epoch of Reionization with 21cm-Lyman- emitter cross-correlation. I
Kenji Kubota, Shintaro Yoshiura, Keitaro Takahashi +5
Detection of the redshifted 21cm-line signal from neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR) is complicated by intense foregrounds su…
Japanese Cosmic Dawn/Epoch of Reionization Science with the Square Kilometre Array
Kenji Hasegawa, Shinsuke Asaba, Kiyotomo Ichiki +10
Cosmic reionization is known to be a major phase transition of the gas in the Universe. Since astronomical objects formed in the early Universe, such as the first stars, galaxies a…
Can the 21 cm signal probe Population III and II star formation?
Hidenobu Yajima, Sadegh Khochfar
Using varying models for the star formation rate (SFR) of Population (Pop) III and II stars at z>6 we derive the expected redshift history of the global 21 cm signal from the inter…
Angular momentum loss of primordial gas in Lyman-alpha radiation field
Hidenobu Yajima, Sadegh Khochfar
We present results on the radiation drag exerted by an isotropic and homogenous background of Lya photons on neutral gas clouds orbiting within HII regions around Population III st…
Dust properties of Lyman break galaxies in cosmological simulations
Hidenobu Yajima, Kentaro Nagamine, Robert Thompson +1
Recent observations have indicated the existence of dust in high-redshift galaxies, however, the dust properties in them are still unknown. Here we present theoretical constraints…
Distinctive 21 cm structures of the first stars, galaxies, and quasars
Hidenobu Yajima, Yuexing Li
Observations of the redshifted 21 cm line with upcoming radio telescopes promise to transform our understanding of the cosmic reionization. To unravel the underlying physical proce…
Effects of photon trapping on the Lyman-alpha properties of star-forming galaxies
Hidenobu Yajima, Yuexing Li
Recent observations show that a large number of Lyman-alpha emitters (LAEs) at high redshift z >= 3 have unusually high Lya equivalent widths (EW > 400 angstrom). However, the orig…
Cold accretion in early galaxy formation and its Lyman-alpha signatures
Hidenobu Yajima, Yuexing Li, Qirong Zhu +1
The Lyman-alpha (Lya) emission has played an important role in detecting high-redshift galaxies, including recently distant ones at redshift z > 7. It may also contain important in…
Extended Lyman-alpha emission from interacting galaxies at high redshifts
Hidenobu Yajima, Yuexing Li, Qirong Zhu
Recent observations have discovered a population of extended Lya sources, dubbed Lyman-alpha blobs (LABs), at high redshift z ~ 3 - 6.6. These LABs typically have a luminosity of L…
Escape of Lyman-alpha and continuum photons from star-forming galaxies
Hidenobu Yajima, Yuexing Li, Qirong Zhu +3
A large number of high-redshift galaxies have been discovered via their narrow-band Lya line or broad-band continuum colors in recent years. The nature of the escaping process of p…
Effect of radiative transfer on damped Lyman-alpha and Lyman limit systems in cosmological SPH simulations
Hidenobu Yajima, Jun-Hwan Choi, Kentaro Nagamine
We study the effect of local stellar radiation and UVB on the physical properties of DLAs and LLSs at z=3 using cosmological SPH simulations. We post-process our simulations with t…
Were progenitors of local L* galaxies Lyman-alpha emitters at high redshift?
Hidenobu Yajima, Yuexing Li, Qirong Zhu +3
The Lya emission has been observed from galaxies over a redshift span z ~ 0 - 8.6. However, the evolution of high-redshift Lya emitters (LAEs), and the link between these populatio…
Sub-millimeter brightness of early star-forming galaxies
Hidenobu Yajima, Masayuki Umemura, Masao Mori
Based on a three-dimensional model of an early star-forming galaxy, we explore the evolution of the sub-millimeter brightness. The model galaxy is employed from an ultra-high-resol…
ART^2 : Coupling Lyman-alpha Line and Multi-wavelength Continuum Radiative Transfer
Hidenobu Yajima, Yuexing Li, Qirong Zhu +1
Narrow-band Lya line and broad-band continuum have played important roles in the discovery of high-redshift galaxies in recent years. Hence, it is crucial to study the radiative tr…
Effects of Ultraviolet Background and Local Stellar Radiation on the H_I Column Density Distribution
Kentaro Nagamine, Jun-Hwan Choi, Hidenobu Yajima
We study the impact of ultraviolet background (UVB) radiation field and the local stellar radiation on the H_I column density distribution f(N_HI) of damped Ly-alpha systems (DLAs)…
Escape fraction of ionizing photons from high-redshift galaxies in cosmological SPH simulations
Hidenobu Yajima, Jun-Hwan Choi, Kentaro Nagamine
Combing the three-dimensional radiative transfer (RT) calculation and cosmological SPH simulations, we study the escape fraction of ionizing photons (f_esc) of high-redshift galaxi…
The escape of ionizing photons from supernova-dominated primordial galaxies
Hidenobu Yajima, Masayuki Umemura, Masao Mori +1
In order to assess the contribution of Lyman break galaxies (LBGs) and Lyman alpha emitters (LAEs) at redshifts 3<z<7 to the ionization of intergalactic medium (IGM), we investigat…