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One of the main goals of the Dark Energy Spectroscopic Instrument (DESI) is to test Einsteins general theory of relativity by measuring the growth of structure with redshift-space distortions. Including direct measurements of galaxy peculiar velocities offer a unique perspective on mass and motions in the low redshift Universe, enabling precision tests of different gravitational models. Using only spare fibres over the lifetime of the DESI survey, we aim to produce the largest catalogue of peculiar velocities ever assembled (30 times larger than the 6dFGSv and 2MTF surveys). This sample will augment constraints on the growth rate of structure from the DESI BGS, reducing the uncertainty by a factor of ~ 2.5 at z < 0.1 compared to the BGS alone. This sample will also enable exquisite tests of the scale-dependence of the growth rate of structure, which cannot be achieved with the BGS alone but is a potential smoking-gun for General Relativity, and provide a legacy sample for correcting the peculiar motions of transients such as those observed by LIGO. The final phase of Survey Validation, the DESI "1%" Survey, was completed on 13/05/2021. During this phase, DESI observed 25,198 galaxies from our FP sample and 4097 galaxies from our TF sample. This is already 3 times the current largest FP sample (6dFGSv) and 2 times the current largest homogeneous TF sample (2MTF). |
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