PI: Tiago Barreiro

Our knowledge about the Universe has improved dramatically over the last two decades. In this period, state of the art cosmological observations have narrowed down the uncertainties in the values of most cosmological parameters below one percent level, paving the way for a new era of precision cosmology. There is still, however, no satisfactory answer to some of the most profound enigmas about the Universe, including the nature of dark matter and dark energy, which could account for about 95% of the energy density of the Universe, and the role played by modified theories of gravity.

At the IA, we are focused on the following topics of research:

• The theoretical modelling of early and late-time cosmological scenarios and the study of their potential impact on the observational properties of the Universe;
• The development of high precision numerical tools to study the non-linear hydrodynamical evolution of galaxies and galaxy clusters and to compute the cosmological evolution of dynamical scalar fields, including topological defects such as cosmic strings and domain walls;
• The application of modern statistical tools for cosmological parameter estimation and model selection, including Markov Chain Monte Carlo sampling, Fisher matrix and principal component analysis;
• The assessment of the performance of competing cosmological paradigms using available and simulated data, including type Ia supernovae, quasar spectra, galaxy clustering, galaxy cluster abundances, cosmic microwave background and weak lensing observations.

The team has been actively involved in several international collaborations, including the Planck survey and the XMM-Newton Cluster Survey (XCS). In the forthcoming years it will continue to play a very active role in the development and scientific exploitation of a new generation of major ESA and ESO facilities, with particular emphasis on Euclid and ESPRESSO in which the IA has an institutional participation (IA is also exploiting possibilities for participation in major future projects such as the proposed ATHENA and eLISA missions).

The scientific preparation of these facilities is a main driver of the forefront research in cosmology, requiring a detailed characterisation of the degeneracies associated with dark energy dynamics, modified models of gravity, variation of fundamental couplings, feedback from small-scale non-linearities and non-gaussianity, as well as a careful modelling of the observational, astrophysical and numerical uncertainties. These are all main axes of research in which the IA team has a consolidated expertise and outstanding long-term contributions.