We study the effects of the ionizing and dissociating photons produced by Pop III objects on the surrounding intergalactic medium. We find that the typical size of a H2 photodissociated region is smaller than the mean distance between sources at z ≈ 20−30, but larger than the ionized region. This implies that clearing of intergalactic H2 occurs before reionization of the universe is complete. I...

The WMAP satellite has measured a large optical depth to electron scattering after cosmological recombination of τes = 0.17 ± 0.04, implying significant reionization of the primordial gas only ∼ 200 million years after the big bang. However, the most recent overlap of intergalactic HII regions must have occurred at z . 9 based on the Lyα forest constraint on the thermal history of the intergala...

We present a new calculation of the intergalactic γray pair-production absorption coefficient as a function of both energy and redshift. In reexamining this problem, we make use of a new empirially based calculation (as opposed to previous model calculations) of the intergalactic infrared radiation field (IIRF). We find smaller opacities than those given previously (Stecker & De Jager 1997). We...

The WMAP satellite has measured a large optical depth to electron scattering after cosmological recombination of τes = 0.17 ± 0.04, implying significant reionization of the primordial gas only ∼ 200 million years after the big bang. However, the most recent overlap of intergalactic HII regions must have occurred at z . 9 based on the Lyα forest constraint on the thermal history of the intergala...

Because observations of galaxies and clusters have been found inconsistent with General Relativity (GR), the focus of effort in developing a Scalar Potential Model (SPM) has been on the examination of galaxies and clusters. The SPM has been found to be consistent with cluster cellular structure, the flow of IGM from spiral galaxies to elliptical galaxies , intergalactic redshift without an expa...

In cosmological models favored by current observations, the first astrophysical objects formed in dark matter halos at redshifts starting at z ∼> 20, and their properties were determined by primordial H2 molecular chemistry. These protogalaxies were very abundant, but substantially less massive than typical galaxies in the local Universe. Extreme metal-poor stars, and massive black holes in the...

The Dark Age is the period between the time when the cosmic microwave background was emitted and the time when the evolution of structure in the universe led to the gravitational collapse of objects, in which the first stars were formed. The period of reionization started with the ionizing light from the first stars, and it ended when all the atoms in the intergalactic medium had been reionized...

Cosmological shock waves are induced during hierarchical formation of large-scale structure in the universe. Like most astrophysical shocks, they are collisionless, since they form in the tenuous intergalactic medium through electromagnetic viscosities. The gravitational energy released during structure formation is transferred by these shocks to the intergalactic gas as heat, cosmic-rays, turb...

We show that the gaseous halos of collapsed objects introduce a substantial cumulative opacity to ionizing radiation, even after the smoothly distributed hydrogen in the intergalactic medium has been fully reionized. This opacity causes a delay of ∆z & 1 in redshift between the time of the overlap of ionized bubbles in the intergalactic medium and the lifting of complete Gunn-Peterson Lyα absor...

A stochastic adhesion model is introduced, with the purpose of describing the formation and evolution of mildly nonlinear structures, such as sheets and filaments, in the intergalactic medium (IGM), after hydrogen reionization. The model is based on replacing the overall force acting on the baryon fluid – as it results from the composition of local gravity, pressure gradients and Hubble drag – ...