The Nature of Dark Matter with Astrophysical Laboratories

The existence of dark matter, which constitutes 85% of the matter density and 26% of the total energy density, is clearly demonstrated by cosmological observations of the Universe. And yet, very little is known about the nature of dark matter. The observations support the ‘cold dark matter’ (CDM) paradigm, in which the dark matter is a heavy particle, with little to no interactions through fundamental forces other than gravity. The cosmological and astrophysical observations of dark matter’s gravitational interaction currently provide the only robust evidence of dark matter. These observations typically rely on characterising the distribution of matter in the Universe. A dark matter particle that is lighter than predicted by the standard CDM paradigm imprints a suppression of structure in the matter distribution. The exact scale where this happens is most often linked to the mass of the dark matter particle. I will review the constraints from the high-redshift cosmic web as traced by the Lyman-alpha forest -- one of the foremost astrophysical laboratories to push the frontiers of the dark matter astrophysics. I will also present new results on the thermal relic warm dark matter and mixed dark matter models using such observations.