Abstract
Even though many scalar field models of dark energy have been considered in the literature, there is another interesting class of dark energy models involving a fluid known as a Chaplygin gas. In addition to describing the dark energy, both scalar-tensor model and the Chaplygin gas model are suitable candidates for explaining the spherical cosmological collapse. One of the most well-known scalar field models is the quintessence model, which was first introduced to explain an accelerating expanding universe. Using a special form of the quintessence model that is equivalent to Chaplygin gas, we describe evolution of a spherical collapse. We study the cosmological properties of the quintessence field with a special potential. In addition to the quintessence model, that can be converted into a Chaplygin gas model in a particular case, we claim that the fixed-potential tachyonic model is equivalent to the Chaplygin gas model. In this work, we obtain the spherical collapse parameters: the virialized over density parameters, radius, the energy density at the turnaround moment, etc. We compare the results of the proposed model with the standard model of cosmology and the Einstein–de Sitter model. We show that the formation of the large-scale structures within the framework of a Chaplygin gas model happens earlier than predicted in the standard model.
Highlights
We show that the formation of structures under the Chaplygin gas model happens faster than what the standard cosmological model predicts
We used the Chaplygin gas model to describe the spherical collapse of the large-scale structures
Potential V (φ) = Numerical analysis of this model showed that for 0.28 ≤ A ≤ 0.55, our model agrees with the current observational results
Summary
One of the most interesting ideas for the unification of dark matter and dark energy is the Chaplygin gas model in which the dark sector of the universe is expressed in terms of a single component that serves for both dark energy and dark matter. The non-linear evolution of structures within the framework of non-minimally coupled quintessence models was studied by Pace et al [7] They conclude that the value of the virial overdensity and the linear density threshold for the spherical collapse are very close to the predictions of the standard cosmological model. In this paper we study the non-linear evolution of structures in the framework of the spherical collapse model using the Chaplygin gas model.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have