arXiv subjects
Publications and source records attributed to Alejandra Kandus.
We study the corrections to the conformal evolution of primordial magnetic fields after recombination, produced by the fall of the ionized fraction of matter into the dark matter gravitational wells. This effect enhances the field around the protostructures being formed, and might help to understand the fields observed in galaxy clusters and hydrogen clouds.
We study the primordial magnetic field generated by stochastic currents produced by scalar charged particles created at the beginning of the radiation dominated epoch. We find that for the mass range 10^(-6)GeV \leq m \leq 10^2 GeV, a field of sufficient intensity to seed different mechanisms of galactic magnetic field generation, while still consistent with observational and theoretical constraints, is created coherently over a galactic scale.
We present an analytical method to extract observational predictions about non linear evolution of perturbations in a Tolman Universe. We assume no a priori profile for them. We solve perturbatively a Hamilton - Jacobi equation for a timelike geodesic and obtain the null one as a limiting case in two situations: for an observer located in the center of symmetry and for a non - centered one. In the first case we find expressions to evaluate the density contrast and the number count and luminosity distance vs redshift relationships up to second order in the perturbations. In the second situation we calculate the CMBR anisotropies at large angular scales produced by the density contrast and by the asymmetry of the observer's location, up to first order in the perturbations. We develope our argument in such a way that the formulae are valid for any shape of the primordial spectrum.