Related papers: Molecules in the early Universe
The synthesis of helium in the early Universe depends on many input parameters, including the value of the gravitational coupling during the period when the nucleosynthesis takes place. We compute the primordial abundance of helium as…
CMBR distortion concerned with recombination of the primordial plasma is calculated in frequency band from 1 GHz to 100 GHz in the frame of the standard cosmological model for different values of cosmological density parameters:…
Recombination of the primordial helium plasma (HeII->HeI, $z \simeq 1500 - 3000$) is considered. This process has an effect on the CMBR anisotropy and CMBR spectrum distortion. In this work an influence of neutral hydrogen on kinetics of…
The first stars in the universe are thought to be massive, forming in dark matter halos with masses around 10^6 solar masses. Recent simulations suggest that these metal-free (Population III) stars may form in binary or multiple systems.…
(Abridged) Cosmology faces three distinct challenges in the next decade. (1) The dark sector, both dark matter and dark energy, dominates the Universe. Key questions include determining the nature of both. Improved observational probes are…
We perform large-scale cosmological simulations that solve Einstein's equations directly via numerical relativity. Starting with initial conditions sampled from the cosmic microwave background, we track the emergence of a cosmic web without…
Here, creation of the universe is obtained only from gravity sector. The dynamical universe begins with two basic ingredients (i) vacuum energy, also called dark energy (as vacuum energy is not observed) and (ii) background radiation. These…
In this paper we explore the potential effects of DM annihilations on the cosmological recombination spectrum. With this example we want to demonstrate that the cosmological recombination spectrum in principle is sensitive to details…
We present a model of the expanding Universe that begins in a zero energy vacuum state. The Universe results from the spontaneous breaking of the electroweak symmetry, wherein the vacuum with positive expectation energy produces the dark…
During its early evolution the Universe provided a laboratory to probe fundamental physics at high energies. Relics from those early epochs, such as the light elements synthesized during primordial nucleosynthesis when the Universe was only…
We discuss the accuracy of the abundance determinations of H II regions in our Galaxy and other galaxies. We focus on the main observational constraints derived from abundance determinations that have implications for models of galactic…
New results, namely the independent determination of the deuterium abundance in several quasar absorption systems, and the complementary determination of the cosmological baryon density by observations of anisotropies in the cosmic…
Dissipative dark matter predicts rich observable phenomena that can be tested with future large-scale structure surveys. As a specific example, we study atomic dark matter, consisting of a heavy particle and a light particle charged under a…
We investigate molecular evolution from a molecular cloud core to a first hydrostatic core in three spatial dimensions. We perform a radiation hydrodynamic simulation in order to trace fluid parcels, in which molecular evolution is…
The standard cosmological model, now strongly constrained by direct observation at early epochs, is very successful in describing the structure of the evolved universe on large and intermediate scales. Unfortunately, serious contradictions…
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…
We investigate the possible impact of diffusion on the abundance of helium and other primordial elements during formation of the first structures in the early Universe. We consider the primary collapse of a perturbation and subsequent…
A key assumption of the standard cosmological model is that the temperature of the cosmic microwave background (CMB) radiation scales with cosmological redshift $z$ as $T_{\rm CMB}(z) \propto (1+z)$ at all times after recombination at…
Assuming that the background geometry is filled with free gas consisting of matter and radiation and no phase transitions being occurred in the early Universe, we discuss the thermodynamics of this {\it closed} system using classical…
Dark photons, a generic class of light gauge bosons that interact with the Standard Model (SM) exclusively through kinetic mixing, arise naturally in many gauge extensions of the SM. Motivated by these theoretical considerations, we present…