相关论文: Constraining Reionization with Lyman Alpha Emittin…
The high-redshift Universe contains luminous Lyman Alpha (hereafter Lya) emitting sources such as galaxies and quasars. The emitted Lya radiation is often scattered by surrounding neutral hydrogen atoms. We show that the scattered Lya…
Several Lyman-alpha (Ly$\alpha$) emitters deep into the reionization era exhibit double-peaked Ly$\alpha$ emission profiles, raising the question of how the intergalactic medium can transmit photons blueward of the Ly$\alpha$ resonance at…
We present high dispersion HST GHRS UV spectroscopic observations of 8 HII galaxies covering a wide range of metallicities and physical properties. We have found Lyalpha emission in 4 galaxies with blueshifted absorption features, leading…
Early results from JWST suggest that epoch-of-reionization (EoR) galaxies produce copious ionizing photons, which, if they escape efficiently, could cause reionization to occur too early. We study this problem using \jwst\ imaging and prism…
We investigate the detectability of Lyman-$\alpha$ (Ly$\alpha$) emission from galaxies at the onset of cosmic reionization, aiming to understand the conditions necessary for detecting high-redshift sources like JADES-GS-z13-1-LA at $z=13$.…
Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha sources based on large simulations of…
Lyman-alpha (Ly$\alpha$) emission from galaxies can be used to trace neutral hydrogen in the epoch of reionization, however, there is a degeneracy between the attenuation of Ly$\alpha$ in the intergalactic medium (IGM) and the line profile…
$\require{mediawiki-texvc}$Given the sensitivity of the resonant Lyman-$\mathrm{\alpha}$ (Ly$\mathrm{\alpha}$) transition to absorption by neutral hydrogen, observations of Ly$\mathrm{\alpha}$ emitting galaxies (LAEs) have been widely used…
The role of higher order Lyman series photons on the 21cm absorption or emission signature of the IGM against the background CMB during the Epoch of Reionisation is examined. It is shown that, taking into account the diminishing resonance…
We perform Monte-Carlo calculations of the radiative transfer of Lyman Alpha (hereafter Lya) photons emitted by a source embedded in a neutral collapsing gas cloud. This represents a young galaxy or quasar during the early stages of the…
Cosmic (hydrogen) reionization marks one of the major phase transitions of the universe at redshift z >= 6. During this epoch, hydrogen atoms in the intergalactic medium (IGM) were ionized by Lyman continuum (LyC) photons. However, it…
The conditions within the ionization front of a quasar during reionization (T ~ 30,000 K, neutral hydrogen fraction ~ 0.5) are ideal for producing Lyman-alpha emission via collisional excitation of hydrogen atoms. Observations of this…
We extend a previous study of Lyman Alpha Emitters (LAEs) based on hydrodynamical cosmological simulations, by including two physical processes important for LAEs: (a) Lyman Alpha and continuum luminosities produced by cooling of…
As Lyman-alpha photons are scattered by neutral hydrogen, a change with redshift in the Lyman-alpha equivalent width distribution of distant galaxies offers a promising probe of the degree of ionization in the intergalactic medium and hence…
Motivated by the claimed detection of a large population of faint active galactic nuclei (AGN) at high redshift, recent studies have proposed models in which AGN contribute significantly to the z > 4 H I ionizing background. In some models,…
A number of independent observations suggest that the intergalactic medium was significantly neutral at $z=7$ and that reionization was, perhaps, still in progress at $z=5.7$. The narrowband survey, SILVERRUSH, has mapped over $2,000$…
We present a quantitative model of Lyman-alpha (Ly-alpha) emission throughout cosmic history and determine the prospects for intensity mapping of spatial fluctuations in the Ly-alpha signal. Since i) our model assumes at z>6 the minimum…
We discuss new constraints on the epoch of cosmic reionization and test the assumption that most of the ionizing photons responsible arose from high redshift star-forming galaxies. Good progress has been made in charting the end of…
The Ly$\alpha$ luminosity function (LF) of Ly$\alpha$ emitters (LAEs) has been used to constrain the neutral hydrogen fraction in the intergalactic medium (IGM) and thus the timeline of cosmic reionization. Here we present the results of a…
We investigate the implications of the intergalactic opacity for the evolution of the cosmic UV luminosity density and its sources. Our main constraint is our measurement of the Lya forest opacity at redshifts 2<z<4.2 from 86…