Related papers: Baryons: What, When and Where?
Reionization, the only phase transition in the Universe since recombination, is a key event in the cosmic history of baryonic matter. We derive, in the context of the large-scale bias expansion, the imprints of the epoch of reionization in…
After recombination the cosmic gas was left in a cold and neutral state. However, as the first stars and black holes formed within early galactic systems, their UV and X-ray radiation induced a gradual phase transition of the intergalactic…
The period in which hydrogen in the intergalactic medium (IGM) is ionized, known as the Epoch of Reionization (EoR) is still poorly understood. The timing and duration of the EoR is expected to be governed by the underlying astrophysics.…
Models predict that chemical enrichment and gas redistribution should proceed rapidly once star formation begins, yet direct observational constraints at the earliest cosmic epochs have been scarce. Here we present evidence that…
The quest to discover the most distant galaxies has developed rapidly in the last decade. We are now exploring redshifts of 6 and beyond, when the Universe was less than a billion years old, an epoch when the previously-neutral…
We present a new analysis of the ionizing emissivity ($\dot{N}_{\rm{ion}}$, s$^{-1}$ Mpc$^{-3}$) for galaxies during the epoch of reionization and their potential for completing and maintaining reionization. We use extensive SED modelling…
We incorporate quasars into an analytic model to describe the reheating and reionization of the universe. In combination with a previous study of galaxies and Lyman-$\alpha$ clouds, we are able to provide a unified description of structure…
I use cosmological simulations that incorporate a physically motivated approximation to three-dimensional radiative transfer that recovers correct asymptotic ionization front propagation speeds for some cosmologically relevant density…
Reionization is thought to have occurred in the redshift range of $6 < z < 9$, which is now being probed by both deep galaxy surveys and CMB observations. Using halo abundance matching over the redshift range $5<z<8$ and assuming smooth,…
A model of the density distribution in the intergalactic medium, motivated by that found in numerical simulations, is used to demonstrate the effect of a clumpy IGM and discrete sources on the reionization of the universe. In an…
In this introductory chapter, we outline expectations for when and how the hydrogen and helium atoms in the universe turned from neutral to ionized, focusing on the earliest, least well understood stages, and emphasizing the most important…
Observations of the 21-centimetre line of atomic hydrogen in the early Universe directly probe the history of the reionization of the gas between galaxies. The observations are challenging, though, because of the low expected signal…
We show the universe was reionized twice, first at z~15-16 and second at z~6. Such an outcome appears inevitable, when normalizing to two well determined observational measurements, namely, the epoch of the final cosmological reionization…
While most of the inter-galactic medium (IGM) today is permeated by ionized hydrogen, it was largely filled with neutral hydrogen for the first 700 million years after the Big Bang. The process that ionized the IGM (cosmic reionization) is…
The cosmic microwave background provides an image of the Universe 0.4 million years after the big bang, when atomic hydrogen formed out of free electrons and protons. One of the primary goals of observational cosmology is to obtain…
Among the light elements created in the Big Bang, deuterium is one of the most difficult to detect but is also the one whose abundance depends most sensitively on the density of baryons. Thus, although we still have only a few positive…
A new parametrization of the reionization history is presented to facilitate robust comparisons between different observations and with theory. The evolution of the ionization fraction with redshift can be effectively captured by specifying…
Characterizing the relationship between stars, gas, and metals in galaxies is a critical component of understanding the cosmic baryon cycle. We compile contemporary censuses of the baryons in collapsed structures, their chemical make-up and…
The standard cosmological model is sufficiently well constrained that precise estimates can be provided for the redshift of various physically defined times in the chronology of the Universe. For example, it is well known that…
Numerical simulations of the intergalactic medium have shown that at the present epoch a significant fraction (40-50%) of the baryonic component should be found in the (T~10^6K) Warm-Hot Intergalactic Medium (WHIM) - with several recent…