A Wide-Field Corrector for the Dark Energy Survey (fEC version)

What is the Universe made of? The recent astronomical measurements suggest a model in which the universe is flat and contains approximately 4% ordinary matter (baryons), 26 % mysterious cold dark matter and 70 % exotic dark energy, with small possible contribution of known massive particles called neutrinos. This model poses fundamental questions about the nature of the dark matter and the dark energy. These topics are of great interest to astronomers, physicists and the general public. We propose to join an international collaboration to conduct the Dark Energy Survey (DES) by helping to build a new wide-field camera for a large telescope in Chile. The planned survey will take place from 2009 to 2014 through 5 observing seasons, approximately 525 nights in total. The survey will provide crude distances for 300 million galaxies one order of magnitude larger than the number of galaxies with available distances to date. It will be used to study galaxy clustering, clusters, standard 'candles' called Supernovae and the bending of light from distant sources by large masses along the line of sight. The primary goal is to accurately determining properties of dark energy and dark matter in the Universe to within few percent. It is proposed that the instrumentation group at UCL (the Optical Science Laboratory) will make a significant in-kind contribution to the optics of the upgraded telescope at a proposed cost of approximately 15% of the total estimated cost of DES. This in-kind contribution will allow UK astronomers to access DES data and to take on leadership roles in key projects on cosmology and galaxy formation. A special benefit to UK astronomers would be the access to both the visible DES data and the infra-red data (from another telescope in Chile called VISTA).