Abstract

In this talk I will introduce two separate strands of work.

The first looks at how violent astrophysical effects can change the distribution of dark matter in galaxies, generating severe difficulties for observers who wish to constrain the nature of the underlying particle. I will suggest avenues of future work that may yet be able to untangle these complexities.

The second concerns dark energy constraints from the observed Lyman-alpha forest. The forest is generally assumed to be a tracer of total matter on large scales but I will show how the assumed link between the dark and observable universe is substantially modified by radiative transfer effects. This generates difficulties for futuristic dark energy surveys like DESI , but also prime opportunities to learn more about the source of ionising photons in our universe.

Through both strands I will discuss analytic, computational and observational progress on the problems.