Target Selection and Validation of DESI Luminous Red Galaxies

By R. Zhou, B. Dey, J. Newman, Daniel J. Eisenstein, K. Dawson, S. Bailey, A. Berti, J. Guy, Ting-Wen Lan, H. Zou and 39 more. Astronomical Journal, 2022

194 citations recorded by the source corpus.

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 using g, r, z, and W1 photometry from the DESI Legacy Imaging Surveys, is highly robust against imaging systematics. The sample has a target density of 605 deg−2 and a comoving number density of 5 × 10−4 h 3 Mpc−3 in 0.4 < z < 0.8; this is a significantly higher density than previous LRG surveys (such as SDSS, BOSS, and eBOSS) while also extending to z ∼ 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 describe the extended LRG samples observed during SV.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/286665302e5945f90e32ce9639f67c28f138e204

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Citations in the corpus

The Early Data Release of the Dark Energy Spectroscopic Instrument (2023, methodology): “The additional LRG selection, named LRG_main, keeps only targets that satisfy the Main Survey selection ( see Zhou et al. 2023 for details ) .”
The DESI Bright Galaxy Survey: Final Target Selection, Design, and Validation (2022, background): “Complementary papers describe the target selection for the dark-time DESI tracers (LRGs; Zhou et al. 2023; ELGs; A. Raichoor et al. 2023, in preparation; and QSOs; Chaussidon et al. 2023) and the Milky Way Survey (MWS; Cooper et al. 2023).”
The Optical Corrector for the Dark Energy Spectroscopic Instrument (2023, background): “The survey will observe four classes of galactic targets: Bright Galaxy Survey targets (BGS, Hahn et al. 2022), luminous red galaxies (LRG, Zhou et al. 2023), emission line galaxies (ELG, Raichoor et al. 2023), and quasi-stellar objects (QSO, Chaussidon et al. 2023).”
Survey Operations for the Dark Energy Spectroscopic Instrument (2023, background): “…et al. 2020; Chaussidon et al. 2023), emission line galaxies with 0.6 < z < 1.6 (Raichoor et al. 2020, 2023), luminous red galaxies with 0.4 < z < 1 (Zhou et al. 2020, 2023), bright galaxies with z < 0.4 (Ruiz-Macias et al. 2020; Hahn et al. 2022), and stars (Allende Prieto et al. 2020; Cooper et…”
Data Release 1 of the Dark Energy Spectroscopic Instrument (2025, unknown): “…galaxy survey ( BGS ) galaxies ( 0 < z < 0.6; O. Ruiz-Macias et al. 2020; C. Hahn et al. 2023 ) ; luminous red galaxies ( LRGs; 0.4 < z < 1.1; R. Zhou et al. 2020, 2023 ) ; emission-line galaxies ( ELGs; 0.6 < z < 1.6; A. Raichoor et al. 2020, 2023 ) ; and QSOs ( 0.9 < z < 4; C. Yèche et al.…”
Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument (2023, methodology): “A full description of the final target selection algorithms for the LRG, ELG, and quasar samples can be found in accompanying papers by Zhou et al. (2023), Raichoor et al. (2023a), and Chaussidon et al. (2023), respectively.”