Related papers: Relative Role of Stars and Quasars in Cosmic Reion…
The temporal evolution of the ionizing UV background radiation field at high redshift provides a probe of the evolution of the early star formation rate. By comparing the observed levels of absorption in the highest redshift quasar spectra…
Quasars are powerful systems whose spectrum is rich of metal features that allow us to investigate the chemical evolution of galaxies at very high redshift, even close to the reionization epoch. I review the main observational constraints…
Observations of QSOs at z ~ 5.7 - 6.4 show the appearance of Gunn-Peterson troughs around z ~ 6, and a change in the slope of the IGM optical depth tau(z) near z ~ 5.5. These results are interpreted as a signature of the end of the…
In this work we investigate the properties of the sources that reionized the intergalactic medium (IGM) in the high-redshift Universe. Using a semi-analytical model aimed at reproducing galaxies and black holes in the first 1.5 Gyr of the…
Using radiative transfer calculations and cosmological simulations of structure formation, we study constraints that can be placed on the nature of the cosmic ultraviolet (UV) background in the redshift interval 2.5< z <5. Our approach…
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 baryon mass content of dark matter halos in the early Universe depends on global factors - e.g. ionising ultraviolet (UV) radiation background - and local factors - e.g. star formation efficiency and assembly history. We use a…
The first generation of redshifted 21 cm detection experiments, carried out with arrays like LOFAR, MWA and GMRT, will have a very low signal-to-noise ratio per resolution element (\sim 0.2). In addition, whereas the variance of the…
A remarkable result of the Wilkinson Microwave Anisotropy Probe (WMAP) observations is that the universe was significantly reionized at large redshifts. The standard explanation is that massive stars formed early and reionized the universe…
Primordial black holes (PBH) could account for variety of phenomena like dark matter, reionization of the Universe, early quasars, coalescence of black holes registered through gravitational waves recently. Each phenomenon relates to PBH of…
The properties of quasar-host galaxies might be determined by the growth and feedback of their supermassive (SMBH, $10^{8-10}$ M$_{\odot}$) black holes. We investigate such connection with a suite of cosmological simulations of massive…
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…
We study the observational signatures of a potential population of low-luminosity quasars at high redshifts in a LambdaCDM cosmology. We derive the evolution of the quasar luminosity function at fainter luminosities and higher redshifts…
I begin by summarizing the evidence that there is a close relationship between the evolution of galaxies and supermassive black holes. They evidently share a common fuel source, and feedback from the black hole may be needed to suppress…
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…
In this talk I discuss the role of proto-globular clusters as the dominant sources of radiation that reionised hydrogen in the intergalactic medium (IGM) at redshift z~6. Observations at lower redshifts indicate that only a small fraction,…
We present the star formation histories, luminosities, colors, mass to light ratios, and halo masses of "galaxies" formed in a simulation of cosmological reionization. We compare these galaxies with Lyman Break Galaxies observed at high…
Using 3D radiative transfer calculations on the reionization of an inhomogeneous universe, QSO absorption line systems are simulated and they are compared with observations of Ly$\alpha$ continuum depression at high redshifts. By this…
Although the mass growth of supermassive black holes during the Epoch of Reionisation is expected to play a role in shaping the concurrent growth of their host-galaxies, observational evidence of feedback at z$\gtrsim$6 is still sparse. We…
The prospect of detecting the first galaxies by observing their impact on the intergalactic medium as they reionized it during the first billion years leads us to ask whether such indirect observations are capable of diagnosing which types…