Astrophysics Colloquium - From Dwarf Galaxies to Dark Matter: Testing Alternatives to ΛCDM model

While the current standard model of cosmology, the so-called ΛCDM model, has been extremely
successful in reproducing the large-scale structure of the Universe, several tensions with
observations have recently emerged, potentially pointing toward new physics and/or alternatives
to cold dark matter.

Dwarf galaxies and ultra-faint dwarf galaxies (UFDs), the faintest objects formed from primordial
density perturbations, provide a powerful laboratory for probing the nature of dark matter
on very small scales. These systems trace physical regimes beyond those typically accessed
by standard methods such as the Lyman-alpha forest, and therefore offer a unique opportunity
to place new constraints on the properties of dark matter.

In this talk, I will first discuss state-of-the-art models of dwarf galaxy formation,
highlighting both their successes in reproducing observed properties of the Universe
and the challenges that remain. I will then explore how alternatives to the ΛCDM
framework can be tested and constrained using dwarf galaxies and UFDs. In particular,
I will examine the impact of primordial magnetic fields as well as self-interacting
dark matter (SIDM) and warm dark matter (WDM) on the properties of those galaxies.