The latest JWST deep observations have the potential of uncovering the nature of dark matter through the investigation of the very early universe. Different dark matter paradigm predicts earlier or later structure formation giving importance to the number of galaxies observed. For this reason, making use of semi-analytic galaxy formation models, I have created a JWST mock galaxy catalogue to study the number counts of galaxies (i.e. counts per unit area and apparent magnitude).
Using the simulated catalogue, a first analysis shows that the counts are dominated by low redshift objects (z<2) hence suggesting that the number counts are not a way to probe the number of high redshift objects, which would be affected by the dark matter scenario. Nevertheless, number counts show a neat change in slope that can be well
reproduced by our models, giving us the possibility to learn about the physics that drives that feature. In this talk, I will explore the physics that can be learnt from the number counts of galaxies and alternative ways that we can use to constraint the nature of dark matter, for example, the prediction on the redshift distributions in the attempt to explain the scarcity of very high redshift objects in comparison to what expected by the standard model of particle CDM.
Modelling the early universe using the James Webb Space Telescope