The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument
Journal
Astronomical Journal
Journal Volume
165
Journal Issue
2
Date Issued
2023-02-01
Author(s)
Myers, Adam D.
Moustakas, John
Bailey, Stephen
Weaver, Benjamin A.
Cooper, Andrew P.
Forero-Romero, Jaime E.
Abolfathi, Bela
Alexander, David M.
Brooks, David
Chaussidon, Edmond
Chuang, Chia Hsun
Dawson, Kyle
Dey, Arjun
Dey, Biprateep
Dhungana, Govinda
Doel, Peter
Fanning, Kevin
Gaztañaga, Enrique
A Gontcho, Satya Gontcho
Gonzalez-Morales, Alma X.
Hahn, Chang Hoon
Herrera-Alcantar, Hiram K.
Honscheid, Klaus
Ishak, Mustapha
Karim, Tanveer
Kirkby, David
Kisner, Theodore
Koposov, Sergey E.
Kremin, Anthony
Landriau, Martin
Lang, Dustin
Levi, Michael E.
Magneville, Christophe
Napolitano, Lucas
Martini, Paul
Meisner, Aaron
Newman, Jeffrey A.
Palanque-Delabrouille, Nathalie
Percival, Will
Poppett, Claire
Prada, Francisco
Raichoor, Anand
Ross, Ashley J.
Schlafly, Edward F.
Schlegel, David
Schubnell, Michael
Tan, Ting
Tarle, Gregory
Wilson, Michael J.
Yèche, Christophe
Zhou, Rongpu
Zhou, Zhimin
Zou, Hu
Abstract
In 2021 May, the Dark Energy Spectroscopic Instrument (DESI) began a 5 yr survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are emission line galaxies, luminous red galaxies, and quasars. In bright time, DESI will focus on two surveys known as the Bright Galaxy Survey and the Milky Way Survey. DESI also observes a selection of “secondary” targets for bespoke science goals. This paper gives an overview of the publicly available pipeline (desitarget) used to process targets for DESI observations. Highlights include details of the different DESI survey targeting phases, the targeting ID (TARGETID) used to define unique targets, the bitmasks used to indicate a particular type of target, the data model and structure of DESI targeting files, and examples of how to access and use the desitarget code base. This paper will also describe “supporting” DESI target classes, such as standard stars, sky locations, and random catalogs that mimic the angular selection function of DESI targets. The DESI target-selection pipeline is complex and sizable; this paper attempts to summarize the most salient information required to understand and work with DESI targeting data.
Type
journal article