Speaker
Description
Recent results from the Dark Energy Spectroscopic Instrument (DESI) suggest that dark energy may evolve over time, potentially challenging the concordance cosmological model. An alternative explanation for dark energy is modified gravity, which predicts different growth rates for cosmic structures in the late universe. The DESI Peculiar Velocity (PV) survey is designed to systematically measure the motions of galaxies at redshifts below 0.15. Combining galaxy redshift measurements with those from the DESI PV survey, we will gain a unique perspective on the distribution and motion of galaxies in the nearby universe, enabling precision tests of gravity and dark energy. In this presentation, I will present an improved maximum-likelihood method to directly fit the peculiar velocity and galaxy overdensity data. We have applied data compression techniques not only to significantly reduce computational time but also to enable us to include previously fixed parameters that we could not include due to computational expense. This new method will be applied to the DR2 data to produce one of the tightest constraints on the growth rate at low redshift and potentially distinguish different models of gravity.
| Other topic / keywords: | Peculiar velocity, DESI |
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