München 2019 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 3: Cosmology I

GR 3.4: Talk

Tuesday, March 19, 2019, 12:15–12:30, HS 4

Influence of baryonic matter on cosmic structure formation with Kinetic Field Theory — •Ivan Kostyuk¹, Robert Lilow², and Matthias Bartelmann¹ — ¹Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, 69120 Heidelberg — ²Department of Physics, Technion, Haifa 3200003, Israel

Baryonic matter with its non-gravitational interactions has profound influence on large-scale cosmic structure formation. To gain an understanding of structure growth it is therefore necessary to investigate how a mixture of dark and baryonic matter coevolves through the cosmic history. To describe this evolution Kinetic Field Theory is used whereby individual classical matter particles are evolved using their Hamiltonian dynamics. To average out frequent microscopic interactions between baryonic particles, they are encapsulated in effective mesoscopic particles which follow the hydrodynamic equations of motion. The main effects of baryons on large scale cosmic structures are of two kinds: firstly through baryon acoustic oscillations in the early Universe, and secondly through pressure and cooling effects in the late Universe. In the first case, we are able to reproduce features of baryon-acoustic oscillations in the spectrum. In the later case, taking into account pressure causes a suppression of power at small scales.