Preliminary Target Selection for the DESI Luminous Red Galaxy (LRG) Sample

TL;DR

This paper presents a preliminary target selection method for the DESI survey's luminous red galaxy sample, aiming for uniform density and low contamination, based on Legacy Surveys Data Release 8 photometry.

Contribution

It introduces a new target selection approach for LRGs in DESI using specific photometric data, with plans for future optimization during survey validation.

Findings

Achieved a uniform surface density of ~600 deg$^{-2}$

Predicted low stellar contamination and redshift failure rates

Method will be refined during DESI Survey Validation

Abstract

The DESI survey will observe more than 8 million candidate luminous red galaxies (LRGs) in the redshift range $0.3<z<1.0$. Here we present a preliminary version of the DESI LRG target selection developed using Legacy Surveys Data Release 8 $g$, $r$, $z$ and $W1$ photometry. This selection yields a sample with a uniform surface density of ${\sim}\,600$ deg$^{-2}$and very low predicted stellar contamination and redshift failure rates. During DESI Survey Validation, updated versions of this selection will be tested and optimized.