Target Selection and Validation of DESI Luminous Red Galaxies
Abstract

The Dark Energy Spectroscopic Instrument (DESI) is carrying out a five-year survey that aims to measure the redshifts of tens of millions of galaxies and quasars, including 8 million luminous red galaxies (LRGs) in the redshift range 0.4 <z≲ 1.0. Here we present the selection of the DESI LRG sample and assess its spectroscopic performance using data from Survey Validation (SV) and the first two months of the Main Survey. The DESI LRG sample, selected usingg,r,z, andW1 photometry from the DESI Legacy Imaging Surveys, is highly robust against imaging systematics. The sample has a target density of 605 deg−2and a comoving number density of 5 × 10−4h3Mpc−3in 0.4 <z< 0.8; this is a significantly higher density than previous LRG surveys (such as SDSS, BOSS, and eBOSS) while also extending toz∼ 1. After applying a bright star veto mask developed for the sample, 98.9% of the observed LRG targets yield confident redshifts (with a catastrophic failure rate of 0.2% in the confident redshifts), and only 0.5% of the LRG targets are stellar contamination. The LRG redshift efficiency varies with source brightness and effective exposure time, and we present a simple model that accurately characterizes this dependence. In the appendices, we more »

Authors:
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Publication Date:
NSF-PAR ID:
10391768
Journal Name:
The Astronomical Journal
Volume:
165
Issue:
2
Page Range or eLocation-ID:
Article No. 58
ISSN:
0004-6256
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
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