DESI Bright Galaxy Survey: Final Target Selection, Design, and Validation
Creators: name: Hahn, ChangHoon
name: Wilson, Michael J.
name: Ruiz-Macias, Omar
name: Cole, Shaun
name: Weinberg, David H.
name: Moustakas, John
name: Kremin, Anthony
name: Tinker, Jeremy L.
name: Smith, Alex
name: Wechsler, Risa H.
name: Ahlen, Steven
name: Alam, Shadab
name: Bailey, Stephen
name: Brooks, David
name: Cooper, Andrew P.
name: Davis, Tamara M.
name: Dawson, Kyle
name: Dey, Arjun
name: Dey, Biprateep
name: Eftekharzadeh, Sarah
name: Eisenstein, Daniel J.
name: Fanning, Kevin
name: Forero-Romero, Jaime E.
name: Frenk, Carlos S.
name: Gaztañaga, Enrique
name: Gontcho, Satya Gontcho A
name: Guy, Julien
name: Honscheid, Klaus
name: Ishak, Mustapha
name: Juneau, Stéphanie
name: Kehoe, Robert
name: Kisner, Theodore
name: Lan, Ting-Wen
name: Landriau, Martin
name: Guillou, Laurent Le
name: Levi, Michael E.
name: Magneville, Christophe
name: Martini, Paul
name: Meisner, Aaron
name: Myers, Adam D.
name: Nie, Jundan
name: Norberg, Peder
name: Palanque-Delabrouille, Nathalie
name: Percival, Will J.
name: Poppett, Claire
name: Prada, Francisco
name: Raichoor, Anand
name: Ross, Ashley J.
name: Safonova, Sasha
name: Saulder, Christoph
name: Schlafly, Eddie
name: Schlegel, David
name: Sierra-Porta, David
name: Tarle, Gregory
name: Weaver, Benjamin A.
name: Yèche, Christophe
name: Zarrouk, Pauline
name: Zhou, Rongpu
name: Zhou, Zhimin
name: Zou, Hu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Over the next five years, the Dark Energy Spectroscopic Instrument (DESI) will use 10 spectrographs with 5000 fibers on the 4m Mayall Telescope at Kitt Peak National Observatory to conduct the first Stage-IV dark energy galaxy survey. At $z &lt; 0.6$, the DESI Bright Galaxy Survey (BGS) will produce the most detailed map of the Universe during the dark energy dominated epoch with redshifts of &gt;10 million galaxies over 14,000 deg$^2$. In this work, we present and validate the final BGS target selection and survey design. From the Legacy Surveys, BGS will target a $r &lt; 19.5$ magnitude-limited sample (BGS Bright); a fainter $19.5 &lt; r &lt; 20.175$ sample, color-selected to have high redshift efficiency (BGS Faint); and a smaller low-z quasar sample. BGS will observe these targets using exposure times, scaled to achieve uniform completeness, and visit each point on the footprint three times. We use observations from the Survey Validation programs conducted prior to the main survey along with realistic simulations to show that BGS can complete its strategy and make optimal use of `bright' time. We demonstrate that BGS targets have stellar contamination &lt;1% and that their densities do not depend strongly on imaging properties. We also confirm that BGS Bright will achieve &gt;80% fiber assignment efficiency. Finally, we show that BGS Bright and Faint will achieve &gt;95% redshift success rates with no significant dependence on observing conditions. BGS meets the requirements for an extensive range of scientific applications. BGS will yield the most precise Baryon Acoustic Oscillations and Redshift-Space Distortions measurements at $z &lt; 0.4$. It also presents opportunities to exploit new methods that require highly complete and dense galaxy samples (e.g. N-point statistics, multi-tracers). BGS further provides a powerful tool to study galaxy populations and the relations between galaxies and dark matter.
description: AJ, submitted, 34 pages, 22 figures, one of a suite of 8 papers detailing targeting for DESI