Dark energy is the most abundant and yet most mysterious substance in the Universe. The existence of dark energy can be inferred by its effects on the expansion rate of the Universe and on the growth of cosmic structures, but its fundamental nature is still completely unknown. The simplest explanation for dark energy, given by a cosmological constant, is also the most successful in reproducing observational data, but lacks a firm theoretical basis and requires an extremely unnatural fine tuning. Alternative models are therefore continuously proposed, and a detailed understanding of their specific observational features is necessary in order to compare different scenarios against data.
In our group we approach the dark energy problem from a phenomenological perspective, by studying the observational effects of different competing models using various observational data-sets and large computer simulations.
Credit: NASA Images/Ann Feild (STScI)