Related papers: Fluctuations in the Ionizing Background During and…
One of the most dramatic signatures of the reionization era may be the enormous ionized bubbles around luminous quasars (with radii reaching ~40 comoving Mpc), which may survive as "fossil'' ionized regions long after their source shuts…
The reionization of cosmic hydrogen marks a critical juncture in the history of structure formation in the universe. Here we present a new formulation of the standard reionization equation for the evolution of the volume-averaged HII…
Lyman-limit absorption systems can play many important roles during and after cosmological reionization. Unfortunately, due to the prohibitively large dynamic range required, it is impossible to self-consistently include these systems in…
Despite decades of effort, the timing and duration of He II reionization, as well as its morphology and the properties of the quasars believed to drive it, are still not well constrained. In this paper we present a new method to study both…
We introduce a new project to understand helium reionization using fully coupled $N$-body, hydrodynamics, and radiative transfer simulations. This project aims to capture correctly the thermal history of the intergalactic medium (IGM) as a…
Recently, we have presented the first large-scale radiative transfer simulations of reionization. Here we present new simulations which extend the source halo mass range downward to 10^8M_solar, to capture the full range of halo masses…
We present cosmological, radiation-hydrodynamics simulations of galaxy formation during the epoch of reionization in an effort towards modelling the interstellar medium (ISM) and interpreting ALMA observations. Simulations with and without…
The spatial correlation between galaxies and the Ly$\alpha$ forest provides insights into how galaxies reionized the Universe. Here, we present initial results on the spatial cross-correlation between [OIII] emitters and Ly$\alpha$ forest…
We present a semi-analytic model for the thermal and ionization history of the universe at 1000 >~ z >~ 3. This model incorporates much of the essential physics included in full-scale hydrodynamical simulations, such as (1) gravitational…
The hyperfine transition of $^3$He$^+$ at 3.5cm has been thought as a probe of the high-z IGM since it offers a unique insight into the evolution of the helium component of the gas, as well as potentially give an independent constraint on…
We investigate the effect of helium on hydrogen reionisation using a hydrodynamical simulation combined with the cosmological radiative transfer code CRASH. The simulations are run in a 35.12/h comoving Mpc box using a variety of…
We constrain the spectrum of the cosmic ultraviolet background radiation by fitting the observed abundance ratios carbon ions at $z\sim 2\hbox{--}3$ with those expected from different models of the background radiation. We use the recently…
We study the observed cosmic ionizing background as a constraint on the nature of the sources responsible for the reionization of the Universe. In earlier work, we showed that extrapolations of the Ultra-Violet Luminosity Function (LF) of…
By using the ultra-deep \textit{JWST}/MIRI image at 5.6 $\mu m$ in the Hubble eXtreme Deep Field, we constrain the role of strong H$\alpha$-emitters (HAEs) during Cosmic Reionization at $z\simeq7-8$. Our sample of HAEs is comprised of young…
Density inhomogeneity in the intergalactic medium (IGM) can boost the recombination rate of ionized gas substantially, affecting the growth of HII regions during reionization. Previous attempts to quantify this effect typically failed to…
Full radiative transfer in 3D space has been solved to pursue the reionization history in an inhomogeneous universe. It has been shown that the reionization of an inhomogeneous universe is not a prompt event, but a fairly slow process.…
Following the completion of cosmic reionization, the mean-free-path of ionizing photons was set by a population of Ly-limit absorbers. As the mean-free-path steadily grew, the intensity of the ionizing background also grew, thus lowering…
The estimate of the ionizing UV background through the proximity effect analysis is discussed. Taking into account the correct bending of the column density distribution which appears in high resolution high s/n data, a value of the UV…
The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a…
We present a formalism for computing time-dependent fluctuations in the cosmological photoionizing radiation background, extending background fluctuations models beyond the steady-state approximation. We apply this formalism to estimate…