Abstract

The epochs of cosmic dawn and reionisation present promising avenues for probing fundamental physics in our cosmos. The first galaxies that populated our Universe during these eras resided in dark-matter halos that were much less massive than their counterparts today. Consequently, observations of such galaxies can provide us with a handle on the properties of matter in an otherwise inaccessible regime. In this talk, I will explain how high-redshift probes, in particular the UV galaxy luminosity-function, can be used to study the clustering of the dark matter. I will highlight the challenges that exist in achieving this goal, in particular our understanding of the halo-galaxy connection, and lay out a roadmap of a possible way to approach this question. Finally, I will also discuss the peculiar results from the first JWST observations, and discuss whether our understanding of cosmology needs to be amended to explain recent claims.