The DESI Bright Galaxy Survey: Final Target Selection, Design, and Validation
Journal
Astronomical Journal
Journal Volume
165
Journal Issue
6
Date Issued
2023-06-01
Author(s)
Hahn, Chang Hoon
Wilson, Michael J.
Ruiz-Macias, Omar
Cole, Shaun
Weinberg, David H.
Moustakas, John
Kremin, Anthony
Tinker, Jeremy L.
Smith, Alex
Wechsler, Risa H.
Ahlen, Steven
Alam, Shadab
Bailey, Stephen
Brooks, David
Cooper, Andrew P.
Davis, Tamara M.
Dawson, Kyle
Dey, Arjun
Dey, Biprateep
Eftekharzadeh, Sarah
Eisenstein, Daniel J.
Fanning, Kevin
Forero-Romero, Jaime E.
Frenk, Carlos S.
Gaztañaga, Enrique
A Gontcho, Satya Gontcho
Guy, Julien
Honscheid, Klaus
Ishak, Mustapha
Juneau, Stéphanie
Kehoe, Robert
Kisner, Theodore
Landriau, Martin
Le Guillou, Laurent
Levi, Michael E.
Magneville, Christophe
Martini, Paul
Meisner, Aaron
Myers, Adam D.
Nie, Jundan
Norberg, Peder
Palanque-Delabrouille, Nathalie
Percival, Will J.
Poppett, Claire
Prada, Francisco
Raichoor, Anand
Ross, Ashley J.
Safonova, Sasha
Saulder, Christoph
Schlafly, Eddie
Schlegel, David
Sierra-Porta, David
Tarle, Gregory
Weaver, Benjamin A.
Yèche, Christophe
Zarrouk, Pauline
Zhou, Rongpu
Zhou, Zhimin
Zou, Hu
Abstract
Over the next 5 yr, the Dark Energy Spectroscopic Instrument (DESI) will use 10 spectrographs with 5000 fibers on the 4 m Mayall Telescope at Kitt Peak National Observatory to conduct the first Stage IV dark energy galaxy survey. At z < 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 >10 million galaxies spanning 14,000 deg2. In this work, we present and validate the final BGS target selection and survey design. From the Legacy Surveys, BGS will target an r < 19.5 mag limited sample (BGS Bright), a fainter 19.5 < r < 20.175 color-selected sample (BGS Faint), and a smaller low-z quasar sample. BGS will observe these targets using exposure times scaled to achieve homogeneous completeness and cover the footprint three times. We use observations from the Survey Validation programs conducted prior to the main survey along with simulations to show that BGS can complete its strategy and make optimal use of “bright” time. BGS targets have stellar contamination <1%, and their densities do not depend strongly on imaging properties. BGS Bright will achieve >80% fiber assignment efficiency. Finally, BGS Bright and BGS Faint will achieve >95% redshift success over any observing condition. BGS meets the requirements for an extensive range of scientific applications. BGS will yield the most precise baryon acoustic oscillation and redshift-space distortion measurements at z < 0.4. It presents opportunities for new methods that require highly complete and dense samples (e.g., N-point statistics, multitracers). BGS further provides a powerful tool to study galaxy populations and the relations between galaxies and dark matter.
SDGs
Type
journal article