München 2019 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

GR: Fachverband Gravitation und Relativitätstheorie

GR 4: Cosmology II

GR 4.4: Vortrag

Dienstag, 19. März 2019, 14:45–15:00, HS 4

A halo mass function from the non-linear density field: an analytic approach — •Johannes Schwinn — ZAH, ITA, Universität Heidelberg, Heidelberg, Germany

The halo mass function is a very important probe for testing cosmological models and our theory of structure formation. However, the only analytical deduction of the halo mass function (apart from fitting formulas) is based on the linear evolution of the cosmic density field and spherical collapse. Since both of these assumptions are not ideal, we derived an analytical estimate of the HMF from the non-linearly evolved density field. Our approach is based on excursion set statistics with correlated steps, which we combine with a PDF model of the cosmic density field. The parameters of this PDF model are fixed by the Kinetic Field Theory (KFT) of cosmic structure formation. This yields a closed-form expression of the HMF that only depends on the overdensity threshold. Treating this threshold as a free parameter, we find very good agreement with measurements from numerical simulations over the mass range from 10¹⁰ to 10¹⁶ M_⊙.