학술논문
Target Selection and Validation of DESI Quasars
Document Type
Working Paper
Author
Chaussidon, Edmond; Yèche, Christophe; Palanque-Delabrouille, Nathalie; Alexander, David M.; Yang, Jinyi; Ahlen, Steven; Bailey, Stephen.; Brooks, David; Cai, Zheng; Chabanier, Solène; Davis, Tamara M.; Dawson, Kyle; de la Macorra, Axel; Dey, Arjun; Dey, Biprateep; Eftekharzadeh, Sarah; Eisenstein, Daniel J.; Fanning, Kevin; Font-Ribera, Andreu; Gaztañaga, Enrique; Gontcho, Satya Gontcho A; Gonzalez-Morales, Alma X.; Guy, Julien; Herrera-Alcantar, Hiram K.; Honscheid, Klaus; Ishak, Mustapha; Jiang, Linhua; Juneau, Stephanie; Kehoe, Robert; Kisner, Theodore; Kovács, Andras; Kremin, Anthony; Lan, Ting-Wen; Landriau, Martin; Guillou, Laurent Le; Levi, Michael E.; Magneville, Christophe; Martini, Paul; Meisner, Aaron M.; Moustakas, John; Muñoz-Gutiérrez, Andrea; Myers, Adam D.; Newman, Jeffrey A.; Nie, Jundan; Percival, Will J.; Poppett, Claire; Prada, Francisco; Raichoor, Anand; Ravoux, Corentin; Ross, Ashley J.; Schlafly, Edward; Schlegel, David; Tan, Ting; Tarlé, Gregory; Zhou, Rongpu; Zhou, Zhimin; Zou, Hu
Source
Subject
Language
Abstract
The Dark Energy Spectroscopic Instrument (DESI) survey will measure large-scale structures using quasars as direct tracers of dark matter in the redshift range 0.92.1. We present several methods to select candidate quasars for DESI, using input photometric imaging in three optical bands (g, r, z) from the DESI Legacy Imaging Surveys and two infrared bands (W1, W2) from the Wide-field Infrared Explorer (WISE). These methods were extensively tested during the Survey Validation of DESI. In this paper, we report on the results obtained with the different methods and present the selection we optimized for the DESI main survey. The final quasar target selection is based on a Random Forest algorithm and selects quasars in the magnitude range 16.599% purity for a nominal effective exposure time of ~1000s. With a 310 per sq. deg. target density, the main selection allows DESI to select more than 200 QSOs per sq. deg. (including 60 quasars with z>2.1), exceeding the project requirements by 20%. The redshift distribution of the selected quasars is in excellent agreement with quasar luminosity function predictions.
Comment: 21 pages, 21 figures, typos corrected, references added
Comment: 21 pages, 21 figures, typos corrected, references added