The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument

Journal Article · 02 March 2023 · The Astronomical Journal

DOI: https://doi.org/10.3847/1538-3881/acb212 · OSTI ID:1959859

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. ; Gaztañaga, E. ; Gontcho A Gontcho, S.; 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. ; Tarlé, Gregory ; Weaver, B. A.; Yéche, Christophe ; Zhou, Rongpu ; Zhou, Zhimin; Zou, H.

Abstract 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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of Michigan, Ann Arbor, MI (United States); University of Rochester, NY (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE Office of Science (SC), High Energy Physics (HEP)
• Contributing Organization: DESI collaboration
• Grant/Contract Number: AC02-05CH11231; SC0008475; SC0019193
• OSTI ID: 1959859
• Journal Information: The Astronomical Journal, Journal Name: The Astronomical Journal Journal Issue: 4 Vol. 165; ISSN 0004-6256
• Publisher: American Astronomical SocietyCopyright Statement
• Country of Publication: United States
• Language: English