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I discuss recent advances in the study of hydrogen reionization, focusing on progress that was achieved during the years 2010-2011. First, I discuss recent measurements of the progress of reionization. Next, I discuss recent observational…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-23 Kristian Finlator

The development of primordial inhomogeneities into the non-linear regime and the formation of the first bound objects mark the transition from a simple cooling universe -- described by just a few parameters -- to a very messy hot one -- the…

Astrophysics · Physics 2009-11-07 Piero Madau

Early galaxies were the radiation source for reionization, with the photoheating feedback from the reionization process expected to reduce the efficiency of star formation in low mass haloes. Hence, to fully understand reionization and…

A variety of observations now indicate that intergalactic helium was fully ionized by z~3. The most recent measurements of the high-redshift quasar luminosity function imply that these sources had produced ~2.5 ionizing photons per helium…

Astrophysics · Physics 2009-11-13 Steven Furlanetto , S. Peng Oh

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…

Astrophysics · Physics 2009-10-31 Nickolay Y. Gnedin

Magnetic fields are ubiquitous in the Universe. They seem to be present at virtually all scales and all epochs. Yet, whether the fields on cosmological scales are of astrophysical or cosmological origin remains an open major problem. Here…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-28 Jean-Baptiste Durrive , Hiroyuki Tashiro , Mathieu Langer , Naoshi Sugiyama

The formation of the first stars and quasars marks the transformation of the universe from its smooth initial state to its clumpy current state. In popular cosmological models, the first sources of light began to form at redshift 30 and…

Astrophysics · Physics 2011-08-23 Rennan Barkana , Abraham Loeb

We have modelled the process of reionization of the IGM by photoionization by galaxies, in order to predict the epoch of reionization. We use a sophisticated semi-analytic model to track the formation of galaxies. Our study represents a…

Astrophysics · Physics 2009-11-11 A. J. Benson , Naoshi Sugiyama , Adi Nusser , C. G. Lacey

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.…

Astrophysics · Physics 2007-05-23 M. Umemura , T. Nakamoto , H. Susa

We use an analytic model to study how inhomogeneous hydrogen reionization affects the temperature distribution of the intergalactic medium (IGM). During this process, the residual energy of each ionizing photon is deposited in the IGM as…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Steven Furlanetto , S. Peng Oh

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…

Astrophysics · Physics 2009-10-31 Weihsueh A. Chiu , Jeremiah P. Ostriker

Energy released by a small fraction of the baryons in the universe, which condensed out of while the IGM was cold, dark, and neutral,reheated and reionized it, exposing gas clouds within it to the glare of ionizing radiation. The first gas…

Astrophysics · Physics 2007-05-23 Paul R. Shapiro , Alejandro C. Raga , Garrelt Mellema

The first major star-forming galaxies and Active Galactic Nuclei will produce Balmer and higher order extended haloes during the Epoch of Reionization through the scattering of Lyman resonance line photons off the surrounding neutral…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Koki Kakiichi , Avery Meiksin , Eric Tittley

The universe was reionized by redshift z ~ 6 by a small fraction of the baryons in the universe, which released energy following their condensation out of a cold, dark, and neutral IGM into the earliest galaxies. The theory of this…

Astrophysics · Physics 2009-11-06 Paul R. Shapiro

In this paper I will discuss the possibility of a reionization of the Universe due to the photons emitted by evaporating primordial black holes (PBHs); this process should happen during the last stages of the PBHs life, when the particle…

Astrophysics · Physics 2011-04-15 Marina Gibilisco

The temperature of the intergalactic medium (IGM) is set by the competition between photoheating and adiabatic cooling, which are usually assumed to define a tight equation of state in which the temperature increases monotonically with…

Astrophysics · Physics 2009-11-13 Steven Furlanetto , S. Peng Oh

Large-scale reionization simulations are described which combine the results of cosmological N-body simulations that model the evolving density and velocity fields and identify the galactic halo sources, with ray-tracing radiative transfer…

The earliest generation of stars, far from being a mere novelty, transformed the universe from darkness to light. The first atoms to form after the Big Bang filled the universe with atomic hydrogen and a few light elements. As gravity…

Astrophysics · Physics 2009-11-11 Rennan Barkana

The intergalactic helium became fully ionized by the end of cosmic noon ($z\sim2$). Similarly to the reionization of hydrogen, helium reionization is expected to be patchy, driven by luminous quasars that ionize the intergalactic gas in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-14 Mesut Çalışkan , Neha Anil Kumar , Selim C. Hotinli , Marc Kamionkowski