Fundamental Cosmology with Euclid Data Exploitation

While the Standard LCDM Cosmological Model of the Universe has been outstandingly successful in accounting for the pattern of fluctuations in the Cosmic Microwave Background, Galaxy Clustering, Weak Lensing and brightness of the Supernova data, the major components of the model, dark energy and dark matter, are poorly understood. Dark matter is required to form the observed large-scale structure and seed galaxy formation, but its composition is unknown.

More problematically, the energy density of the Universe is dominated by a mysterious, negative pressure 'dark energy' which is causing the expansion to accelerate. This is accounted for in the model by a classical Cosmological Constant, but this has huge quantum vacuum contributions which are sensitive to unknown physics. New mechanisms to dampen these contribution have been proposed, leading to new fields and modifications to gravity at low energies which can affect both the expansion history and formation of structure in the Universe.

ESA's flagship Euclid Dark Energy Satellite Mission was designed to identify the nature of dark matter, detect deviations from a Cosmological Constant, or find evidence for new forces or changes in gravity. Its main probes are Weak Gravitational Lensing, which uses small distortions of galaxy images due to the intervening matter to map out the dark matter distribution, and Galaxy Clustering using the angular and redshift positions of galaxies, which can probe both structure formation and the expansion history of the Universe.

The main Euclid Wide Field Survey, covering 15,000 square degrees, is designed to measure the dark energy equation-of-state to a precision of less than 1%. Euclid is scheduled for Launch in July 2023, with a first Internal Consortium Data Release of 2,500 square degrees in Nov 2024 and a Public Data Release in Nov 2025. This dataset will be much larger than any previous Weak Gravitational Lensing and Galaxy Clustering survey and requires new analysis techniques to reach the required accuracy and precision.

This project is the develop and apply new, advanced analysis methods to the Euclid data to measure the properties of the dark energy and the dark matter to high precision and determine their nature, measure the mass of the the neutrinos and measure the properties of the Universe at lower redshift.