Speaker
Description
Cosmological perturbation theory provides the fundamental framework for describing the evolution of the matter-energy density field in an expanding universe and serves as the basis for understanding the formation of large-scale structures within the $\Lambda$CDM paradigm. In this work, we present an analytical approach to describe the evolution of fluctuations—small deviations from the mean density—in a mixed fluid composed of cold dark matter (CDM) and baryonic matter. Assuming that the universe is governed by General Relativity (GR), we employ the Vlasov equation to derive the general equations of motion for this system, incorporating baryonic effects through the stress tensor by considering only the contributions from baryonic pressure. We then introduce the Jeans Filtering Functions (JFF) as a biasing tool that allows us to describe baryonic fluctuations by using CDM as a tracer through analytical methods. First- and second-order solutions are obtained through a single iteration. Finally, we highlight analytical solutions for baryonic fluctuations in the density and velocity fields, which can be readily computed and provide insights into the role of baryons in the Large-Scale Structure (LSS) of the Universe.
