What is COMAP?

The CO Mapping Array Project (COMAP) is part of a program aiming to trace the spatial distribution of star-forming galaxies at the Epoch of Reionization (EoR).

Constraining the CO power spectrum from the EoR will ultimately require measurements at multiple frequencies and focal-plane arrays with hundreds of elements. As a first step towards this goal, COMAP: Pathfinder comprises a 10.4-m telescope, located at the Owens Valley Radio Observatory (OVRO), equipped with a 19-pixel spectrometer array that is mapping a total of around 12 square degrees of sky in the frequency range 26-34 GHz, with spectral resolution R~800. This band is sensitive to CO(1-0) in the redshift slice z=2.4-3.4 and to CO(2-1) in the redshift slice z = 5.8-7.8. A CASPER-based digital backend is used to process 8 GHz from each of the 19 pixels.

The aim of this Pathfinder is to i) demonstrate the feasibility and future potential of wide-field CO intensity mapping, and ii) provide a test-bed for the technology development and observational strategies. The science focus of the Pathfinder is on detecting the CO power spectrum and deriving constraints on the global properties of galaxies at z=2.4-3.4. The next stage of the experiment, COMAP:EoR, will provide constraints on galaxies through the end of the Epoch of reionization, at z=4.5-8, as well as adding sensitivity at z=2-3.

Nov 2021: Early Science papers on arxiv!

Latest COMAP Collaboration Publications

  • Cleary+ 2021: "COMAP Early Science: I. Overview"
  • Lamb+ 2021: "COMAP Early Science: II. Pathfinder Instrument"
  • Foss+ 2021: "COMAP Early Science: III. CO Data Processing"
  • Ihle+ 2021: "COMAP Early Science: IV. Power Spectrum Methodology and Results"
  • Chung+ 2021a: "COMAP Early Science: V. Constraints and Forecasts at z~3"
  • Rennie+ 2021: "COMAP Early Science: VI. A First Look at the COMAP Galactic Plane Survey"
  • Breysse+ 2021: "COMAP Early Science: VII. Prospects for CO Intensity Mapping at Reionization"
  • Silva+ 2021: "Synergies between the COMAP CO Line Intensity Mapping mission and a Lyα galaxy survey: How to probe the early universe with voxel based analysis of observational data"
  • Chung+ 2021: "A model of spectral line broadening in signal forecasts for line-intensity mapping experiments"

COMAP Science & Instrument


Although the ultimate goal of COMAP is to target the EoR, Phase I will focus on the lower redshifts accessible to a Pathfinder-scale experiment: z = 2.4 - 3.4, at the peak of the cosmic star-formation rate density, during the Epoch of Galaxy Assembly.


COMAP Phase I is a single-dish experiment, using a 19-feed focal plane array operating at 26-34 GHz, deployed on a 10.4-m telescope at the Owens Valley Radio Observatory.