Journal Article

The DESI DR1 Peculiar Velocity Survey: Global Zero-point and H0 Constraints

Ferraro, S, Ross, C, de la Macorra, A, Turner, R. J, Gaztañaga, E, Palmese, A, Carr, A, Joyce, R, Prada, F, Said, K, Miquel, R, Zhou, R, Claybaugh, T, Seo, H, Percival, W. J, Bianchi, D, Blake, C, Pérez-Ràfols, I, Weaver, B. A, Lamman, C, Manera, M, Herrera-Alcantar, H. K, Parkinson, D, Douglass, K, ero-Romero, J. E, Gontcho A Gontcho, S, Moustakas, J, Aguilar, J, Honscheid, K, Sanchez, E, Kim, A. G, Bautista, J, Landriau, M, Huterer, D, Davis, Tamara M, Schlegel, D, Sprayberry, D, Le Guillou, L, Howlett, C, Tarlé, G, Brooks, D, Doel, P, Kremin, A, Amsellem, A. J, Nadathur, S, Kirkby, D, Meisner, A, Levi, M. E, Zarrouk, P, Lahav, O, Gutierrez, G, Qin, F, Ahlen, S, Cuceu, A, BenZvi, S, Rossi, G, Zou, H, Ishak, M

2026

Overview

The Dark Energy Spectroscopic Instrument (DESI) in its first Data Release (DR1) already provides more than 100,000 galaxies with relative distance measurements. The primary purpose of this paper is to perform the calibration of the zero-point for the DESI Fundamental Plane and Tully–Fisher relations, which allows us to measure the Hubble constant, H0. This sample has a lower statistical uncertainty than any previously used to measure H0, and we investigate the systematic uncertainties in absolute calibration that could limit the accuracy of that measurement. We improve upon the DESI Early Data Release Fundamental Plane H0 measurement by (a) using a group catalog to increase the number of calibrator galaxies and (b) investigating alternative calibrators in the nearby Universe. Our baseline measurement calibrates to the SH0ES/Pantheon+ type Ia supernovae, and finds H0 = 73.7 ± 0.06 (stat.) ± 1.1 (syst.) km s−1 Mpc−1. Calibrating to surface brightness fluctuation distances yields a similar H0. We explore measurements using other calibrators, but these are currently less precise since the overlap with DESI peculiar velocity tracers is much smaller. In future data releases with an even larger peculiar velocity sample, we plan to calibrate directly to Cepheids and the tip of the red giant branch, which will enable the uncertainty to decrease towards a percent-level measurement of H0. This will provide an alternative to supernovae as the Hubble flow sample for H0 measurements.

• Publisher: IOP Publishing
• Subject: Calibration / Dark energy / Distance measurement / Galaxies / Hubble constant / Supernovae / Surface brightness / Tracers / Tully-Fisher relation / Uncertainty