Related papers: Structure formation in inhomogeneous Early Dark En…
We consider a generic type of dark energy fluid, characterised by a constant equation of state parameter w and sound speed c_s, and investigate the impact of dark energy clustering on cosmic structure formation using the spherical collapse…
The evolution of the perturbations in the energy density and the particle number density in a flat Friedmann-Lemaitre-Robertson-Walker universe in the radiation-dominated era and in the epoch after decoupling of matter and radiation is…
We explore the effect of substructure in dark matter halos on the power spectrum and bispectrum of matter fluctuations and weak lensing shear. By experimenting with substructure in a cosmological N = 512^3 simulation, we find that when a…
Interaction between dark matter and dark energy as one of not completely solved problems in cosmology has been studied extensively. This interaction affects the cosmic structures. In this regard, the shape of cosmic voids can be influenced…
We analyze the properties of dark matter halos in the cold-plus-warm dark matter cosmologies (CWDM). We study their dependence on the fraction and velocity dispersion of the warm particle, keeping the free-streaming scale fixed. To this end…
The intra-cluster medium is prone to turbulent motion that will contribute to the non-thermal heating of the gas, complicating the use of galaxy clusters as cosmological probes. Indirect approaches can estimate the intensity and structure…
The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish…
We develop the halo model of large-scale structure as an accurate tool for probing primordial non-Gaussianity. In this study we focus on understanding the matter clustering at several redshifts. The primordial non-Gaussianity is modeled as…
We study the spherical collapse of non-top-hat matter fluctuations in the presence of dark energy with arbitrary sound speed. The model is described by a system of partial differential equations solved using a pseudo-spectral method with…
Structure formation provides a strong test of any cosmic acceleration model because a successful dark energy model must not inhibit {\black or overpredict} the development of observed large-scale structures. Traditional approaches to…
We derived the influence of dark matter (DM) decays and annihilations on structure formation. The energy deposited by DM decays and annihilations into metal free halos both increases the gas temperature and enhances the formation of…
The growth of the density fluctuations is considered to be an important cosmological test. In the standard model, for a matter dominated universe, the growth of the density perturbations evolves with redshift z like (1/{1+z))^s with s=1.…
We study how the evolution of a Dark Energy Quintessence fluid is modified by the presence of a matter inhomogeneity. To do so, we study linear perturbations of a flat FLRW background containing dust and a slowly rolling scalar field. Under…
We investigate the growth of matter fluctuations in holographic dark energy cosmologies. First we use an overall statistical analysis involving the latest observational data in order to place constraints on the cosmological parameters. Then…
We discuss the influence of dark energy on structure formation, especially the effects on \sigma_8. Our interest is particularly focused on quintessence models with time-dependent equation of state and non-negligible quintessence component…
We propose that dark matter (DM) possesses a quadratic equation of state, which becomes significant at high densities, altering the Universe's evolution during its early stages. We derive the modified background evolution equations for the…
Non-linear gravitational clustering in a universe dominated by dark energy, modelled by a `quintessence' scalar field, and cold dark matter with space-time varying mass is studied. Models of this type, where the variable mass is induced by…
All models of dynamical dark energy possess fluctuations, which affect the number of galaxy clusters in the Universe. We have studied the impact of dark energy clustering on the number of clusters using a generalization of the spherical…
The structure and dynamics of dark matter halos, as predicted by the hierarchical clustering scenario, are at odds with the properties inferred from the observations at galactic scales. My Thesis addresses this problem by taking an…
There is a plethora of dark energy parameterizations that can fit current supernovae Ia data. However, this data is only sensitive to redshifts up to order one. In fact, many of these parameterizations break down at higher redshifts. In…