Leads: Ian McCarthy, Joop Schaye, Matthieu Schaller & Virgo II

The worldwide observational cosmology community is gearing up to receive a real deluge of new data from large survey campaigns currently mapping the sky. This data will allow, for the first time, to put tight constraints on some key properties of our standard cosmological model as well as measure the mass of the neutrino. However, to interpret this data, equally precise and accurate models of the universe must be available. Furthermore, model variations have to be designed so as to encompass the whole parameter range in which our Universe lies. 

The Virgo Consortium’s FLAMINGO project is designed to provide exactly the virtual twins of our Universe that will be used alongside these modern surveys. The project includes the largest cosmological simulation with gas ever run (shown above left) as well as the largest simulation ever run including neutrinos, one of the key parameters we hope to constrain. However, as argued, having one single simulation is not sufficient to encompass the real of plausible universes. FLAMINGO has been extended, using DiRAC time, to include many variations. In these,  we vary the neutrino masses and the background cosmology.

Besides targeting the largest ever simulations, the other feature that sets the project apart is the variations of the galaxy formation aspects. The details of how galaxies form, and especially how their central supermassive black hole interact with their environment are still too poorly understood for the requirement of the era of precision cosmology. In this project, we thus decided to vary wildly the model by scaling the effect of the black holes up and down by large fractions. This will be of crucial importance to teams attempting to marginalise over this effect in the data.  In the right hand figure we show the relative effects on the matter power spectrum due to these variations compated to a dark matter only universe. Our library of runs shows large multi-percent variations, which will be crucial to take into account when attempting to measure the key parameters of our Universe with sub-percent accuracy.