Related papers: Constraints on Vacuum Energy from Structure Format…
We discuss the present bounds on the relativistic energy density in the Universe parameterized in terms of the effective number of neutrinos N using the most recent cosmological data on Cosmic Microwave Background (CMB) temperature…
We present new Big Bang Nucleosynthesis (BBN) limits on the cosmic expansion rate or relativistic energy density, quantified via the number $N_\nu$ of equivalent neutrino species. We use the latest light element observations, neutron mean…
We combine complementary datasets to constrain dark energy. Using standard Big Bang Nucleosynthesis and the observed abundances of primordial nuclides to put constraints on $\Omega_Q$ at temperatures near $T \sim 1MeV$, we find the strong…
Big Bang Nucleosynthesis (BBN), as one of the earliest processes in the universe accessible to direct observation, offers a powerful and independent probe of the cosmic expansion history. With recent advances in both theory and observation,…
To elucidate the significance of the effect of systematic uncertainties in light element abundance estimates on cosmological bounds derivable from Big Bang Nucleosynthesis (BBN) we present tables giving bounds on $\Omega_{baryon}$ and…
Structure formation creates high temperature and density regions in the Universe that allow the conversion of matter into more stable states, with a corresponding emission of relativistic matter and radiation. An example of such a mechanism…
A dark radiation term arises as a correction to the energy momentum tensor in the simplest five-dimensional RS-II brane-world cosmology. In this paper we revisit the constraints on dark radiation based upon the newest results for…
We derive constraints on the injection of free-streaming dark radiation after big bang nucleosynthesis (BBN) by considering the decay of a massive hidden sector particle into dark radiation. Such a scenario has the potential to alleviate…
One of the greatest challenges in cosmology today is to determine the nature of dark energy, the source of the observed present acceleration of the universe. High precision experiments are being developed to reduce the uncertainties in the…
We use Big Bang Nucleosynthesis (BBN) data in order to impose constraints on higher-order modified gravity, and in particular on: (i) $f(G)$ Gauss-Bonnet gravity, and $f(P)$ cubic gravities, arising respectively through the use of the…
We have derived new bounds on the relativistic energy density in the Universe from cosmic microwave background (CMB), large scale structure (LSS), and type Ia supernova (SNI-a) observations. In terms of the effective number of neutrino…
In this work, we impose observational limits on the product of dark energy chemical potential, $\mu$, and number density, $n$, at the present time in out-of-equilibrium models, considering that particles can be created or destroyed in the…
A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity…
During the process of structure formation in the universe matter is converted into radiation through a variety of processes such as light from stars, infrared radiation from cosmic dust and gravitational waves from binary black…
We present a model-independent reconstruction of the early expansion and thermal histories of the universe, obtained from light element abundance measurements. The expansion history is tightly constrained around the onset of the Big Bang…
We forecast the expected cosmological constraints from a combination of probes of both the universal expansion rate and matter perturbation growth, in the form of weak lensing tomography, galaxy tomography, supernovae, and the cosmic…
The cosmological constant, which was introduced by Einstein a century ago to allow for a static universe, experienced a revival two decades ago under the label dark energy as a parameter to model the observed accelerated expansion of the…
We use Big Bang Nucleosynthesis (BBN) data in order to impose constraints on the exponent of Barrow entropy. The latter is an extended entropy relation arising from the incorporation of quantum-gravitational effects on the black-hole…
We consider the effect of three species of neutrinos with nearly degenerate mass on the cosmic structure formation in a low matter-density universe within a hierarchical clustering scenario with a flat initial perturbation spectrum. The…
Full suite of the present day Cosmic Microwave background (CMB) data, when combined with weak prior information on the Hubble constant and the age of the Universe, or the Large-Scale structure, provides strong indication for a non-zero…