0000000000815495
AUTHOR
Diego Saez
Gravitational waves from galaxy cluster distributions
Galaxy clusters are sources of gravitational radiation. The main aim of this paper is to give numerical estimates and theoretical description of the relevant features of the gravitational radiation coming from an appropriate spatial distributions of galaxy clusters. Since no analytical approaches are currently available to describe the strongly nonlinear regime, our numerical approach - combining numerical simulations with statistical arguments - seems to be an useful way of studying the main features of that radiation. Although far to be detectable with present technology, we advance some ideas about future observational strategies and its cosmological implications.
On the role of shock waves in galaxy cluster evolution
Numerical simulations of galaxy clusters including two species -- baryonic gas and dark matter particles --are presented. Cold Dark Matter spectrum, Gaussian statistics and flat universe are assumed. The dark matter component is evolved numerically by means of a standard particle mesh method. The evolution of the baryonic component has been studied numerically by using a multidimensional (3D) hydrodynamical code based on modern high resolution shock capturing techniques. These techniques are specially designed for treating accurately complex flows in which shocks appear and interact. With this picture, the role of shock waves in the formation and evolution of rich galaxy clusters is analyze…
General Relativistic Dynamics of Irrotational Dust: Cosmological Implications
The non--linear dynamics of cosmological perturbations of an irrotational collisionless fluid is analyzed within General Relativity. Relativistic and Newtonian solutions are compared, stressing the different role of boundary conditions in the two theories. Cosmological implications of relativistic effects, already present at second order in perturbation theory, are studied and the dynamical role of the magnetic part of the Weyl tensor is elucidated.