Related papers: Reionization of the Intergalactic Medium
The intergalactic medium - the cosmic gas that fills the great spaces between the galaxies - is affected by processes ranging from quantum fluctuations in the very early universe to radiative emission from newly-formed stars. This gives the…
The universe goes through several phase transitions during its formative stages. Cosmic reionization is the last of them, where ultraviolet and X-ray radiation escape from the first generations of galaxies heating and ionizing their…
In popular cosmological scenarios, some time beyond a redshift of 10, stars within protogalaxies created the first heavy elements; these systems, together perhaps with an early population of quasars, generated the ultraviolet radiation and…
Reionization represents an important phase in the history of our Universe when ultraviolet radiation from the first luminous sources, primarily stars and accreting black holes, ionized the neutral hydrogen atoms in the intergalactic medium…
Reionization is a process whereby hydrogen (and helium) in the Universe is ionized by the radiation from first luminous sources. Theoretically, the importance of the reionization lies in its close coupling with the formation of first cosmic…
The transformation of cold neutral intergalactic hydrogen into a highly ionized warm plasma marks the end of the cosmic dark ages and the beginning of the age of galaxies. The details of this process reflect the nature of the early sources…
The Universe's dark ages end with the formation of the first generation of galaxies. These objects start emitting ultraviolet radiation that carves out ionized regions around them. After a sufficient number of ionizing sources have formed,…
The modeling of galaxy formation and reionization, two central issues of modern cosmology, relies on the accurate follow-up of the intergalactic medium (IGM). Unfortunately, owing to the complex nature of this medium, the differential…
A major goal of observational and theoretical cosmology is to observe the largely unexplored time period in the history of our universe when the first galaxies form, and to interpret these measurements. Early galaxies dramatically impacted…
After the so-called cosmic recombination, the expanding universe entered into a period of darkness since most of the matter was in a neutral state. About a billion years later, however, the intergalactic space was once again ionized. The…
The Cosmic Dark Ages mark a pivotal era of the universe's evolution, transitioning from a neutral, opaque medium to the emergence of the first stars and galaxies that initiated cosmic reionization. This study examines the thermodynamics of…
In popular cold dark matter cosmological scenarios, stars may have first appeared in significant numbers around a redshift of 10 or so, as the gas within protogalactic halos with virial temperatures in excess of 20,000 K (corresponding to…
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…
The cosmic dawn and epoch of reionization mark the time period in the universe when stars, galaxies, and blackhole seeds first formed and the intergalactic medium changed from neutral to an ionized one. Despite substantial progress with…
The study of cosmic reionization has acquired increasing significance over the last few years because of various reasons. On the observational front, we now have good quality data of different types at high redshifts (quasar absorption…
The epoch of reionization probes the state of our universe when the very first stars formed and ionized the hydrogen atoms in the surrounding medium. Since the epoch has not yet been probed observationally, it is often called the "final…
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…
The first sources of ionizing radiation to condense out of the dark and neutral IGM sent ionization fronts sweeping outward through their surroundings, overtaking other condensed objects and photoevaporating them. This feedback of universal…
This thesis investigates the Epoch of Cosmic Reionization (EoR), a key period in the early Universe when the first luminous sources formed and their radiation transformed the intergalactic medium (IGM) from neutral to ionized. Understanding…
The cosmic reionization of hydrogen was the last major phase transition in the evolution of the universe, which drastically changed the ionization and thermal conditions in the cosmic gas. To the best of our knowledge today, this process…