UCL Astrophysics Group

TESTDE: Testing the Dark Energy paradigm and measuring neutrino mass with the Dark Energy Survey

One of the greatest mysteries in the whole of science is that 70% of the Universe appears to be made of an enigmatic ‘Dark Energy’. A further 25% of the Universe is made from invisible ‘Cold Dark Matter’ that can only be detected through its gravitational effects, with the ordinary atomic matter making up only 5% of the total cosmic budget. These discoveries require a shift in our perception. UCL Cosmology play leadership roles in several large surveys, in particular the $40M international Dark Energy Survey (DES), the data from which is key to exploring the themes below.

'First-light' for the survey camera, DECam, was in September 2012 with the Dark Energy Survey formally starting in August 2013. In February 2015, the second year of DES observations was successfully completed.  UCL plays a key role within the collaboration - see DES@UCL pages.

There are three themes for the TESTDE project, which are interlinked:

  1. Modelling the cross-talk of DES probes and a feasibility study for a spectroscopic follow-up (DESI) which will allow testing modified General Relativity models as alternatives to Dark Energy;
  2. Attempting for the first time to measure the as yet unknown neutrino mass from DES, including novel modelling of the non-linear power spectrum; and
  3. Follow up of an intriguing excess in galaxy clustering on large scales we recently detected in our home-grown MegaZ-LRG sample, and developing new approaches to photometric redshifts.
The synergy among the observational and theoretical parts of the TESTDE project, and their relation to the three themes: modelling Dark Energy & alternatives; photometric redshifts; and neutrino mass.
The synergy among the observational and theoretical parts of the TESTDE project, and their relation to the three themes: modelling Dark Energy & alternatives; photometric redshifts; and neutrino mass.

The research is interdisciplinary since it is connected to statistical methods as well as to High Energy Physics. The techniques developed will also be used for many other projects, including the ongoing Hubble Space Telescope CLASH survey of clusters and the planned ESA Euclid space mission. 

TESTDE is a €2.4M project funded by the European Research Council as an Advanced Grant awarded to Prof. Ofer Lahav, which started in May 2012.

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Page last modified on 04 mar 15 15:00 by Joanna Fabbri