First Detection of the BAO Signal from Early DESI Data

ORAL

Abstract

We present the detection of the baryon acoustic oscillations (BAO) signal using unblinded data collected during the initial two months of operations of the Stage-IV ground-based Dark Energy Spectroscopic Instrument (DESI). From 261,291 Luminous Red Galaxies spanning redshifts 0.4 < z < 1.1 and 1651 sq. deg. with a 57.9% completeness, we report a 5σ level BAO detection at a precision of 1.7%. Using 630,480 Bright Galaxy Sample over 0.1 < z < 0.5, 3677 sq. deg. with a 50.0% completeness, we also detect the BAO feature at 3σ significance with a 2.6% precision. These are an important milestone which confirms the choice of the survey design, quality performance of the complex robotically-actuated, fiber-fed DESI spectrograph, validates the 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 a sub-percent accuracy with the completed 5-year survey data, meeting the Level 1 science requirements on BAO measurement precision. This will set novel standards in cosmology, and confirm DESI as one of the most competitive Stage-IV BAO experiments for large-scale spectroscopic surveys for the remainder of this decade.

*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. DE–AC02–05CH11231, 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 by the DESI Member Institutions: https://www.desi.lbl.gov/collaborating-institutions.The authors are honored to be permitted to conduct scientific research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation.

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Publication: First Detection of the BAO Signal from Early DESI Data (2023, planned)

Presenters

  • Michael Rashkovetskyi

    • Center for Astrophysics | Harvard & Smithsonian

Authors

  • Michael Rashkovetskyi

    • Center for Astrophysics | Harvard & Smithsonian

  • Graziano Rossi

    • Sejong University

  • Jeongin Moon

    • Sejong University

  • Christoph Saulder

    • Korea Astronomy and Space Science Institute

  • David Valcin

    • Ohio University

  • Nikhil Padmanabhan

    • Yale University

  • Hee-Jong Seo

    • Ohio University

  • Arnaud de Mattia

    • Saclay - Commissariat à l'énergie atomique et aux énergies alternatives

  • Ashley J Ross

    • Ohio State University