Fredagskollokvium: Probing fundamental physics with clusters of galaxies

Steffen Hagstotz, Stockholm University 

Steffen Hagstotz, Stockholm University. Foto: Steffen Hagstotz

The highest peaks in the cosmic density field host large clusters of galaxies that are

observable over vast distances. Their abundance is a sensitive probe of the physics of structure formation, and in my talk I will explain how clusters can be used to study effects of neutrinos or look for signatures of modified gravity.

These massive overdensities are only a small part of the complicated large-scale structure in the universe today. Gravitational collapse turns the smooth initial conditions into the cosmic web we observe today, consisting of filaments that surround large void regions. Galaxy clusters form in the knots of this cosmic web, and in the second part of the talk I will outline how to connect their number to the non-Gaussian shape of the underlying dark matter field which is not captured by the power spectrum or related two-point statistics that are commonly used in cosmology.

Distribution of matter in a numerical simulation of cosmic structure formation. The picture is roughly 900 million light years in width, and shows the cosmic web (mostly consisting of dark matter) with hot gas (shown in red) forming galaxies along the filaments and very massive galaxy clusters where these filaments intersect. Studying the abundance of these galaxy clusters, we can learn more about the invisible underlying dark matter structures. Image credits: Klaus Dolag (LMU in Munich).


Publisert 8. jan. 2019 18:44 - Sist endret 24. sep. 2019 13:04