Related papers: Cosmic reionization in a dynamic quintessence cosm…
One of the most sought-after signatures of reionization is a rapid increase in the ionizing background (usually measured through the Lyman-alpha optical depth toward distant quasars). Conventional wisdom associates this with the "overlap"…
In quintessence models, the dark energy content of the universe is described by a slowly rolling scalar field whose pressure and energy density obey an equation of state of the form p=w $\rho$; w is in general a function of time such that…
The visibility of LyA emitting galaxies during the Epoch of Reionization is controlled by both diffuse HI patches in large-scale bubble morphology and small-scale absorbers. To investigate the impact on LyA photons, we apply a novel…
Using the CoDa II simulation, we study the Ly$\alpha$ transmissivity of the intergalactic medium (IGM) during reionization. At $z>6$, a typical galaxy without an active galactic nucleus fails to form a proximity zone around itself due to…
By depleting the ionizing photon budget available to expand cosmic HII regions, recombining systems (or Lyman limit systems) can have a large impact during (and following) cosmic reionization. Unfortunately, directly resolving such…
We consider a five-dimensional Ricci flat Bouncing cosmology and assume that the four-dimensional universe is permeated smoothly by three minimally coupled matter components: CDM+baryons $\rho_{m}$, radiation $\rho_{r}$ and dark energy…
The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10^5 to 10^6 Msun. These stars photo-ionize their host primordial molecular…
The central overlap phase of cosmological hydrogen reionization is fundamentally a change in the topology of ionized regions. Before overlap, ionized bubbles grew in isolation. During overlap, they merge into a percolating ionized medium,…
We perform fits of unconventional dark energy models to the available data from high-redshift supernovae, distant galaxies and baryon oscillations. The models are based either on brane cosmologies or on Liouville strings in which a…
The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish…
We show that the cosmic star formation rate per comoving volume should exhibit a distinct drop around the reionization redshift, when the HII regions in the intergalactic medium around individual ionizing sources first overlapped. The drop…
In this paper we investigate how the Reionization process is affected by early galaxy formation in different cosmological scenarios. We use a semi-analytic model with suppressed initial power spectra to obtain the UV Luminosity Function in…
We study the observed cosmic ionizing background as a constraint on the nature of the sources responsible for the reionization of the Universe. In earlier work, we showed that extrapolations of the Ultra-Violet Luminosity Function (LF) of…
The feedback effects of massive stars on their galactic and intergalactic environments can dominate evolutionary processes in galaxies and affect cosmic structure in the Universe. Only the Local Group offers the spatial resolution to…
Imagine a scenario in which the dark energy forms via the condensation of dark matter at some low redshift. The Compton wavelength therefore changes from small to very large at the transition, unlike quintessence or metamorphosis. We study…
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…
We investigate various dark energy models by taking into account the thermal effects induced from Hawking radiation on the apparent horizon of the Universe, for example near a finite-time future singularity. If the dark energy density…
We explore the dynamics of cosmological models with two coupled dark components with energy densities $\rho_A$ and $\rho_B$. We assume that the coupling is of the form $Q=Hq(\rho_A,\rho_B)$, so that the dynamics of the two components turns…
We extend the existing analytical model of reionization by Furlanetto et al. (2004) to include the biasing of reionization sources and additional absorption by Lyman Limit systems. Our model is, by construction, consistent with the observed…
Molecular clouds interacting with supernova remnants may be subject to a greatly enhanced irradiation by cosmic rays produced at the shocked interface between the ejecta and the molecular gas. Over the past decade, broad-band observations…