“Illuminating the dark sector of the Universe” ATCAM project (2019-T1/TIC-12702)

This project aims to understand the dark sector of the Universe studying the galaxies that trace it. This sector constitutes over 95% of the total energy-matter content of the Universe. Its nature remains unknown, despite decades of continuous effort. In the next years cosmological galaxy surveys will focus on the characterisation of the dark sector of the Universe. This observational characterisation relies on having an improved understanding of galaxies as cosmological tracers. We urgently need to answer the following questions:

  • How can theoretical models aid and support the interpretation of cosmological observations?
  • How do galaxies trace the dark sector?
  • How affected are cosmological probes by galaxy formation?
  • How do galaxies trace the dark sector when different cosmologies (the global composition of the Universe) are assumed?

Answering these questions will get us closer to understanding the nature of our Universe. The theoretical development from this project will support the success of space missions, such as Euclid (to be launch in 2021), and ground telescopes, such as the LSST (to start operating in 2023). Investments of millions of euros have been made in these and other ones, such eBOSS, DESI, WFIRST, etc.

The team will use a range of theoretical approaches to answer the questions above. The choice of theoretical tools will vary depending on the level of spatial and stellar mass detail needed. This research programme focuses on the epoch when the Universe was less than half its present age. We will study theoretically the types of galaxies targeted by cosmological surveys.

General objectives

  1. Support cosmological surveys by: (i) providing new and improved parametrisations for halo occupation models, (ii) generating new model galaxy catalogues tailored for surveys and (iii) suggesting observables to discern between different cosmological models.
  2. Establish how galaxies trace the dark sector within the standard cosmology by exploring the properties of those galaxies targeted by cosmological studies with semi-analytical and hydro-dynamical simulations.
  3. Quantify the impact of galaxy formation and evolution on cosmological probes by comparing models with different assumptions about the physical processes that shape galaxies.
  4. Establish how galaxies trace the dark sector beyond the standard cosmology using an adequate suite of simulations.