Related papers: Spherical Collapse for Viscous Generalized Chaplyg…
We propose a renormalizable model with no fundamental scalars which breaks itself in the manner of a "tumbling" gauge theory down to the standard model with a top-quark condensate. Because of anomaly cancellation requirements, this model…
We study the gravitational clustering of spherically symmetric overdensities and the statistics of the resulting dark matter halos in the "symmetron model", in which a new long range force is mediated by a $Z_2$ symmetric scalar field.…
The abundance of massive dark matter halos hosting galaxy clusters provides an important test of the masses of relic neutrino species. The dominant effect of neutrino mass is to lower the typical amplitude of density perturbations that…
Gaussian process latent variable models (GPLVMs) are a versatile family of unsupervised learning models commonly used for dimensionality reduction. However, common challenges in modeling data with GPLVMs include inadequate kernel…
We present an analytical model for the non-spherical collapse of overdense regions out of a Gaussian random field of initial cosmological perturbations. The collapsing region is treated as an ellipsoid of constant density, acted upon by the…
We investigate the formation of spherical cosmological structures following both dark matter and gas components. We focus on the dynamical aspect of the collapse assuming an adiabatic, $\gamma = 5/3$, fully ionized primordial plasma. We use…
We perform a numerical study of the critical regime for the general relativistic collapse of collisionless matter in spherical symmetry. The evolution of the matter is given by the Vlasov equation (or Boltzmann equation) and the geometry by…
The spherical collapse scenario has great importance in cosmology since it captures several crucial aspects of structure formation. The presence of self-similar solutions in the Einstein-de Sitter (EdS) model greatly simplifies its…
In this paper, we use the latest observations of quasars covering the redshift range of $0.04<z<5.1$ to investigate a series of Chaplygin gas models as candidates for unified dark matter and dark energy. Based on different combinations of…
We study the dependence of the location of the Cosmic Microwave Background Radiation (CMBR) peaks on the parameters of the generalized Chaplygin gas model, whose equation of state is given by $p = - A/\rho^{\alpha}$, where $A$ is a positive…
Collapse of the rotating spheroid is approximated by a system of ordinary differential equations describing its dynamics. The gravitational potential is approximated by the one of the iniform Maclaurin spheroid. Developement of…
The possibility of dark matter being a dissipative component represents an option for the standard view where cold dark matter (CDM) particles behave on large scales as an ideal fluid. By including a physical mechanism to the dark matter…
We solve numerically the equations of motion for the collapse of a shell of baryonic matter, made of galaxies and substructure of $ 10^{6} M_{\odot} \div 10^{9} M_{\odot}$, taking into account the dynamical friction and the parameters on…
We find the general solution of the Einstein equation for spherically symmetric collapse of Type II fluid (null strange quark fluid) in higher dimensions. It turns out that the nakedness and curvature strength of the shell focusing…
A spherically symmetric collapsing scalar field model is discussed with a dissipative fluid which includes a heat flux. This vastly general matter distribution is analyzed at the expense of a high degree of symmetry in the space-time, that…
We consider a scenario where the interior spacetime,described by a heat conducting fluid sphere is matched to a Vaidya metric in higher dimensions.Interestingly we get a class of solutions, where following heat radiation the boundary…
We study the formation of the (noncommutative) Schwarzschild black hole from collapsing shell {of the} generalized matters containing polytropic and Chaplygin gas. We show that this collapsing shell depending on various parameters forms…
Cosmological Perturbation Theory (PT) is a useful tool to study the cumulants of the density and velocity fields in the large scale structure of the Universe. In Papers I & II of this series we saw that the Spherical Collapse (SC) model…
In the present work, we investigate cosmological perturbations of viscous modified chaplygin gas model. Using 1 + 3 covariant formalism, we define covariant and gauge invariant gradient variables, which after the application of scalar…
We treat here general relativistically the issue of galaxy formation, which is a major problem in cosmology. While the current models use a top-hat collapse model, coupled with Newtonian virialization technique to balance the…