First detection of the BAO signal from early DESI data
Jeongin Moon, D. Valcin, M. Rashkovetskyi, Christoph Saulder, J. Aguilar, S. P. Ahlen, Shadab Alam, S. Bailey, C. Baltay, Robert Blum, D. Brooks, E. Burtin, E. Chaussidon, Kyle Dawson, Axel de la Macorra, Arnaud de M attia, G. Dhungana, Daniel J. Eisenstein, B. Flaugher, Andreu Font-Ribera, J. E. Forero-Romero, C. García-Quintero, Satya Gontcho A Gontcho, Julien Guy, M. Hanif, Klaus Honscheid, Mustapha Ishak, R. Kehoe, Sumi Kim, Theodore Kisner, Anthony Kremin, Martin Landriau, L. Le Guillou, Michael Levi, Marc Manera, Paul Martini, Patrick McDonald, Aaron Meisner, Ramon Miquel, John Moustakas, Adam Myers, S. Nadathur, Richard Neveux, Jeffrey A. Newman, Jundan Nie, Nikhil Padmanabhan, N. Palanque‐Delabrouille, Will J. Percival, Alejandro Pérez Fernández, Claire Poppett, Francisco Prada, Anand Raichoor, Ashley J Ross, Graziano Rossi, Lado Samushia, David J. Schlegel, Hee‐Jong Seo, G. Tarlé, M. Vargas-Magaña, Andrei Variu, Benjamin Alan Weaver, Martin White, Christophe Yèche, Sihan Yuan, Cheng Zhao, Rongpu Zhou, Zhimin Zhou, Hu Zou
Abstract
ABSTRACT We present the first detection of the baryon acoustic oscillations (BAOs) signal obtained using unblinded data collected during the initial 2 months of operations of the Stage-IV ground-based Dark Energy Spectroscopic Instrument (DESI). From a selected sample of 261 291 luminous red galaxies spanning the redshift interval 0.4 < z < 1.1 and covering 1651 square degrees with a 57.9 per cent completeness level, we report a ∼5σ level BAO detection and the measurement of the BAO location at a precision of 1.7 per cent. Using a bright galaxy sample of 109 523 galaxies in the redshift range 0.1 < z < 0.5, over 3677 square degrees with a 50.0 per cent completeness, we also detect the BAO feature at ∼3σ significance with a 2.6 per cent precision. These first BAO measurements represent an important milestone, acting as a quality control on the optimal performance of the complex robotically actuated, fibre-fed DESI spectrograph, as well as an early validation of the DESI spectroscopic pipeline and data management system. Based on these first promising results, we forecast that DESI is on target to achieve a high-significance BAO detection at sub-per cent precision with the completed 5-yr survey data, meeting the top-level science requirements on BAO measurements. This exquisite level of precision will set new standards in cosmology and confirm DESI as the most competitive BAO experiment for the remainder of this decade.