Probing dark energy and gravity in the nearby universe with the DESI peculiar velocity survey
ORAL · Invited
Abstract
Recent results from the Dark Energy Spectroscopic Instrument (DESI) hints 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 of cosmic structures in the late universe. The DESI Peculiar Velocity (PV) survey is designed to systematically measure the motions of galaxies below redshift of 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. The first DESI PV data release contains around 100,000 galaxy velocity measurements, twice as many as in any previous catalogues, and enables a 12% precision measurement on the growth rate. We also demonstrate, for the first time, that different methods yield consistent growth rate constraints with the same data. Furthermore, we generated the largest set of mocks of galaxy density and peculiar velocity from simulations. Additionally, combining our growth rate measurements with those from high-redshift in DESI improves constraints on the redshift evolution of the growth rate by a factor of two compared to using high-redshift data alone. Our growth rate measurements and its redshift evolution show consistency with General Relativity's predictions. Future data releases will use more galaxies and provide even stronger constraints on the growth rate and modified gravity models.
*This work is supported by the U.S. Department of Energy, Office of Science, Office of High-Energy Physics, under Contract No. DE–AC02–05CH11231, and by the National Energy Research Scientific Computing Center. Additional support for DESI was provided by the U.S. NSF under Contract No. AST-0950945; the STFC of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French CEA; the CONAHCYT of Mexico; the MICIU of Spain, and by the DESI Member Institutions. The authors are honored to conduct research on I'oligam Du'ag, a mountain particularly significant to the Tohono O’odham Nation. For more information, visit desi.lbl.gov.
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Publication:We aims to submit the following paper by the end of December 2025. The presentation will present the results from these papers. 1. The DESI DR1 Peculiar Velocity Survey: global zero-point and H0 constraints. 2. The DESI DR1 Peculiar Velocity Survey: growth rate measurements from galaxy and momentum correlation functions. 3. DESI DR1 Peculiar Velocity Survey: Fundamental Plane Catalogue. 4. The DESI DR1 Peculiar Velocity Survey: Growth Rate Measurements from the Galaxy Power Spectrum. 5. The DESI DR1 Peculiar Velocity Survey: growth rate measurements from the maximum likelihood fields method. 6. The DESI DR1 Peculiar Velocity Survey: The Tully-Fisher Distance Catalog. 7. The DESI DR1 Peculiar Velocity Survey: Mock Catalogs.
