CaltechAUTHORS
Published July 10, 2022 | Version Published + Accepted Version
Journal Article Open

COMAP Early Science. IV. Power Spectrum Methodology and Results

Creators

  • 1. ROR icon University of Oslo
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon University of Manchester
  • 4. ROR icon Jet Propulsion Lab
  • 5. ROR icon National Radio Astronomy Observatory
  • 6. ROR icon Canadian Institute for Theoretical Astrophysics
  • 7. ROR icon University of Toronto
  • 8. ROR icon New York University
  • 9. ROR icon Stanford University
  • 10. ROR icon University of Miami
  • 11. ROR icon University of Maryland, College Park
  • 12. ROR icon University of Geneva

Abstract

We present the power spectrum methodology used for the first-season COMAP analysis, and assess the quality of the current data set. The main results are derived through the Feed–Feed Pseudo-Cross-Spectrum (FPXS) method, which is a robust estimator with respect to both noise modeling errors and experimental systematics. We use effective transfer functions to take into account the effects of instrumental beam smoothing and various filter operations applied during the low-level data processing. The power spectra estimated in this way have allowed us to identify a systematic error associated with one of our two scanning strategies, believed to be due to residual ground or atmospheric contamination. We omit these data from our analysis and no longer use this scanning technique for observations. We present the power spectra from our first season of observing, and demonstrate that the uncertainties are integrating as expected for uncorrelated noise, with any residual systematics suppressed to a level below the noise. Using the FPXS method, and combining data on scales k = 0.051–0.62 Mpc⁻¹, we estimate P_(CO(k)) = −2.7 ± 1.7 × 10⁴ μK² Mpc³, the first direct 3D constraint on the clustering component of the CO(1–0) power spectrum in the literature.

Additional Information

© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 November 19; revised 2022 February 25; accepted 2022 March 25; published 2022 July 13. Focus on Early Science Results from the CO Mapping Array Project (COMAP). This material is based upon work supported by the National Science Foundation, under grant Nos. 1517108, 1517288, 1517598, 1518282, and 1910999, and by the Keck Institute for Space Studies, under "The First Billion Years: A Technical Development Program for Spectral Line Observations." Parts of the work were carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration, and funded through the internal Research and Technology Development program. D.T.C. is supported by a CITA/Dunlap Institute postdoctoral fellowship. The Dunlap Institute is funded through an endowment established by the David Dunlap family and the University of Toronto. C.D. acknowledges support from an STFC Consolidated Grant (ST/P000649/1). J.B., H.K.E., M.K.F., H.T.I., J.G.S.L., M.R., N.O.S., D.W., and I.K.W. acknowledge support from the Research Council of Norway through grants 251328 and 274990, and from the European Research Council (ERC) under the Horizon 2020 Research and Innovation Program (grant agreement No. 819478, Cosmoglobe). J.G. acknowledges support from the University of Miami and is grateful to Hugh Medrano for assistance with cryostat design. S.H. acknowledges support from an STFC Consolidated Grant (ST/P000649/1). J.K. is supported by a Robert A. Millikan Fellowship from Caltech. At JPL, we are grateful to Mary Soria for assembly work on the amplifier modules and to Jose Velasco, Ezra Long, and Jim Bowen for the use of their amplifier test facilities. H.P. acknowledges support from the Swiss National Science Foundation through Ambizione Grant PZ00P2_179934. P.C.B. is supported by the James Arthur Postdoctoral Fellowship. We thank Isu Ravi for her contributions to the warm electronics and antenna–driven characterization. The scientific color maps roma and tokyo (Crameri 2021) are used in this study to prevent visual distortion of the data and exclusion of readers with color-vision deficiencies (Crameri et al. 2020). Finally, we want to thank the anonymous referee, whose comments and suggestions have helped to improve and clarify this manuscript. Software: Matplotlib (Hunter 2007); Astropy, a community-developed core Python package for astronomy (Astropy Collaboration et al. 2013).

Attached Files

Published - Ihle_2022_ApJ_933_185.pdf

Accepted Version - 2111.05930.pdf

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Additional details

Identifiers

Eprint ID
115917
Resolver ID
CaltechAUTHORS:20220727-38447000

Related works

Describes
https://arxiv.org/abs/2111.05930 (URL)

Funding

NSF
AST-1517108
NSF
AST-1517288
NSF
AST-1517598
NSF
AST-1518282
NSF
AST-1910999
Keck Institute for Space Studies (KISS)
NASA/JPL/Caltech
JPL Internal Research and Technology Development Program
Canadian Institute for Theoretical Astrophysics
Dunlap Institute for Astronomy and Astrophysics
University of Toronto
Science and Technology Facilities Council (STFC)
ST/P000649/1
Research Council of Norway
251328
Research Council of Norway
274990
European Research Council (ERC)
819478
University of Miami
Robert A. Millikan Fellowship
Swiss National Science Foundation (SNSF)
PZ00P2_179934
James Arthur Fellowship

Dates

Created
2022-07-28
Created from EPrint's datestamp field
Updated
2022-07-28
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Astronomy Department, Infrared Processing and Analysis Center (IPAC), Keck Institute for Space Studies, Owens Valley Radio Observatory