Constraints over Cosmological Constant and Quintessence Fields in an Accelerating Universe

TL;DR

This paper reviews current cosmological observations and discusses how constraints from nucleosynthesis and galaxy formation limit the parameters of dark energy models, comparing the evolution of DM and DM cosmologies.

Contribution

It develops a realistic approach to the tracking behavior of quintessence fields and constrains DM and DM models using astrophysical data.

Findings

Transition to acceleration occurs earlier in DM than in QCDM.

Astrophysical constraints suggest DM models have specific limits on .

Tracking parameter   0.75 at present epoch.

Abstract

A brief account of the current cosmological observations is given and their implications for QCDM and $\Lambda$CDM cosmologies are discussed. The nucleosynthesis and the galaxy formation constraints have been used to put limits on $\Omega_\phi$ during cosmic evolution, and develop a realistic approach to the tracking behaviour of quintessence fields. The astrophysical constraints are applied to interpolate the value of the tracking parameter $\epsilon \simeq 0.75$ at the present epoch and also to find the lower and the upper limits for $\Lambda$ in the accelerating universe. It is shown that the transition from deceleration to acceleration in the cosmic expansion occurs earlier in $\Lambda$CDM cosmology compared to QCDM cosmology.