相关论文: Reionisation: the role of Globular Clusters
Constraints on the ionization structure of the Intergalactic Medium are derived as directly imposed by observations in conjunction with the results of numerical simulations for structure formation. Under the assumption that the population…
Galaxy clusters are the most massive, gravitationally-bound structures in the Universe, emerging through hierarchical structure formation of large-scale dark matter and baryon overdensities. Early galaxy ``proto-clusters'' are believed to…
The reionization of cosmic hydrogen, left over from the big bang, increased its temperature to >~ 1.e4 K. This photo-heating resulted in an increase of the minimum mass of galaxies and hence a suppression of the cosmic star formation rate.…
Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate…
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,…
The critical star formation rate density required to keep the intergalactic hydrogen ionised depends crucially on the average rate of recombinations in the intergalactic medium (IGM). This rate is proportional to the clumping factor C =…
We determine the abundance of i'-band drop-outs in the HST/ACS GOODS surveys and the Hubble Ultra Deep Field (UDF). The majority of these sources are likely to be z~6 galaxies whose flux decrement arises from Lyman-alpha absorption. We have…
Globular clusters are unique tracers of ancient star formation. We determine the formation efficiencies of globular clusters across cosmic time by modeling the formation and dynamical evolution of the globular cluster population of a Milky…
Understanding the role of high-redshift protoclusters in cosmic reionization is essential to unveiling the early stages of structure formation. Using deep imaging and spectroscopy from the James Webb Space Telescope (JWST) JADES Deep Survey…
The physical basis for the belief that the abundant old dwarf galaxies seen in present-day galaxy clusters formed before reionization of the universe is very compelling, because (1) the observed faint end slope of the galaxy luminosity…
The intergalactic medium was reionized before redshift z~6, most likely by starlight which escaped from early galaxies. The very first stars formed when hydrogen molecules (H2) cooled gas inside the smallest galaxies, minihalos of mass…
The history of the transition from a neutral intergalactic medium to one that is almost fully ionized can reveal the character of cosmological ionizing sources. In this talk I will discuss the implications for rival reionization scenarios…
We consider the early stages of cosmic hydrogen or helium reionization, when ionizing sources were still rare. We show that Poisson fluctuations in the galaxy distribution substantially affected the early bubble size distribution, although…
A fundamental requirement for reionizing the Universe is that a sufficient fraction of the ionizing photons emitted by galaxies successfully escapes into the intergalactic medium. However, due to the scarcity of high-redshift observational…
Cosmic (hydrogen) reionization marks one of the major phase transitions of the universe at redshift z >= 6. During this epoch, hydrogen atoms in the intergalactic medium (IGM) were ionized by Lyman continuum (LyC) photons. However, it…
We study the formation of molecular hydrogen, after the epoch of re-ionization, in the context of canonical galaxy formation theory due to hierarchical clustering. There is an initial epoch of $H_2$ production in the gas phase through the…
Our understanding of radiative feedback and star formation in galaxies at high redshift is hindered by the rarity of similar systems at low redshift. However, the recently identified Green Pea (GP) galaxies are similar to high-redshift…
The reionization history of the intergalactic medium (IGM) at high redshift (z > 6) was likely strongly shaped by several global feedback processes. Because the earliest ionizing sources formed at the locations of the rare density peaks,…
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…
Globular clusters will be present at high redshifts, near the very beginning of the galaxy formation process. Stellar evolution ensures that they will be much more luminous than today. We show that the redshift distribution at nano-Jansky…