The DESI DR1 Peculiar Velocity Survey: Fundamental Plane Catalogue

TL;DR

This paper presents the largest catalog of peculiar velocity measurements at low redshift using the Fundamental Plane method from DESI DR1, enabling improved studies of dark energy.

Contribution

It provides the first extensive FP-based peculiar velocity catalog from DESI DR1, doubling the number of such measurements at z<0.1 and detailing the data quality and systematics checks.

Findings

Catalog contains 98,292 early-type galaxies with peculiar velocities.

Achieves 26% random error in distance measurements.

Enables future cosmological parameter estimation.

Abstract

Measurements of peculiar velocities in the local Universe are a powerful tool to study the nature of dark energy at low ($z < 0.1$) redshifts. Here we present the largest single set of $z<0.1$ peculiar velocity measurements to date, obtained using the Fundamental Plane (FP) of galaxies in the first data release (DR1) of the Dark Energy Spectroscopic Instrument (DESI). We describe the photometric and spectroscopic selection criteria used to define the sample, as well as extensive quality control checks on the photometry and velocity dispersion measurements. Additionally, we perform detailed systematics checks for the many analysis parameters in our pipeline. Our DESI DR1 catalogue contains FP-based distances and peculiar velocities for $98,292$ unique early-type galaxies, increasing the total number of $z < 0.1$ FP distances ever measured by a factor of $\sim2$. We achieve a precision of $26\%$ random error in our distance measurements which is comparable to previous surveys. A series of companion DESI papers use the distances and peculiar velocities presented in this paper to measure cosmological parameters.