Full list of authors: Guy, J.; Bailey, S.; Kremin, A.; Alam, Shadab; Alexander, D. M.; Allende Prieto, C.; BenZvi, S.; Bolton, A. S.; Brooks, D.; Chaussidon, E.; Cooper, A. P.; Dawson, K.; de la Macorra, A.; Dey, A.; Dey, Biprateep; Dhungana, G.; Eisenstein, D. J.; Font-Ribera, A.; Forero-Romero, J. E.; Gaztanaga, E.; Gontcho, S. Gontcho A.; Green, D.; Honscheid, K.; Ishak, M.; Kehoe, R.; Kirkby, D.; Kisner, T.; Koposov, Sergey E.; Lan, Ting-Wen; Landriau, M.; Le Guillou, L.; Levi, Michael E.; Magneville, C.; Manser, Christopher J.; Martini, P.; Meisner, Aaron M.; Miquel, R.; Moustakas, J.; Myers, Adam D.; Newman, Jeffrey A.; Nie, Jundan; Palanque-Delabrouille, N.; Percival, W. J.; Poppett, C.; Prada, F.; Raichoor, A.; Ravoux, C.; Ross, A. J.; Schlafly, E. F.; Schlegel, D.; Schubnell, M.; Sharples, Ray M.; Tarle, Gregory; Weaver, B. A.; Yeche, Christophe; Zhou, Rongpu; Zhou, Zhimin; Zou, H.--This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
We describe the spectroscopic data processing pipeline of the Dark Energy Spectroscopic Instrument (DESI), which is conducting a redshift survey of about 40 million galaxies and quasars using a purpose-built instrument on the 4 m Mayall Telescope at Kitt Peak National Observatory. The main goal of DESI is to measure with unprecedented precision the expansion history of the universe with the baryon acoustic oscillation technique and the growth rate of structure with redshift space distortions. Ten spectrographs with three cameras each disperse the light from 5000 fibers onto 30 CCDs, covering the near-UV to near-infrared (3600–9800 Å) with a spectral resolution ranging from 2000 to 5000. The DESI data pipeline generates wavelength- and flux-calibrated spectra of all the targets, along with spectroscopic classifications and redshift measurements. Fully processed data from each night are typically available to the DESI collaboration the following morning. We give details about the pipeline's algorithms, and provide performance results on the stability of the optics, the quality of the sky background subtraction, and the precision and accuracy of the instrumental calibration. This pipeline has been used to process the DESI Survey Validation data set, and has exceeded the project's requirements for redshift performance, with high efficiency and a purity greater than 99% for all target classes. © 2023. The Author(s). Published by the American Astronomical Society.
This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under contract No. DEAC0205CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract; additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under contract No. AST-0950945 to the NSF's National Optical-Infrared Astronomy Research Laboratory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico (CONACYT); the Ministry of Science and Innovation of Spain (MICINN); and the DESI Member Institutions: https://www.desi.lbl.gov/collaborating-institutions. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Source data files for the plots are archived at 10.5281/zenodo.7087815.
With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).