{"work":{"id":"be71acab-27de-43a6-9a9f-4aa8c3c733bb","openalex_id":null,"doi":null,"arxiv_id":"2208.08515","raw_key":null,"title":"Target Selection and Validation of DESI Luminous Red Galaxies","authors":null,"authors_text":"R","year":2022,"venue":"astro-ph.CO","abstract":"The Dark Energy Spectroscopic Instrument (DESI) is carrying out a 5-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 of $0.4<z<{\\sim}\\,1.0$. Here we present the selection of the DESI LRG sample and assess its spectroscopic performance using data from Survey Validation (SV) and the first 2 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 $5\\times10^{-4}\\ h^3\\mathrm{Mpc}^{-3}$ 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 $z \\sim 1$. 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.","external_url":"https://arxiv.org/abs/2208.08515","cited_by_count":null,"metadata_source":"pith","metadata_fetched_at":"2026-07-10T18:37:31.113188+00:00","pith_arxiv_id":"2208.08515","created_at":"2026-05-10T22:40:49.313333+00:00","updated_at":"2026-07-10T18:37:31.113188+00:00","title_quality_ok":true,"display_title":"Zhou , B","render_title":"Zhou , B"},"hub":{"state":{"work_id":"be71acab-27de-43a6-9a9f-4aa8c3c733bb","tier":"hub","tier_reason":"10+ Pith inbound or 1,000+ external citations","pith_inbound_count":25,"external_cited_by_count":null,"distinct_field_count":3,"first_pith_cited_at":"2024-04-03T18:41:49+00:00","last_pith_cited_at":"2026-07-08T19:18:54+00:00","author_build_status":"not_needed","summary_status":"needed","contexts_status":"needed","graph_status":"needed","ask_index_status":"not_needed","reader_status":"not_needed","recognition_status":"not_needed","updated_at":"2026-08-22T00:39:42.583019+00:00","tier_text":"hub"},"tier":"hub","role_counts":[{"context_role":"background","n":8},{"context_role":"dataset","n":6},{"context_role":"method","n":2},{"context_role":"baseline","n":1}],"polarity_counts":[{"context_polarity":"background","n":8},{"context_polarity":"use_dataset","n":6},{"context_polarity":"use_method","n":2},{"context_polarity":"baseline","n":1}],"runs":{},"summary":{},"graph":{},"authors":[]}}