COMAP Early Science: V. Constraints and Forecasts at $z\sim 3$

Abstract

We present the current state of models for the $z\sim 3$ carbon monoxide (CO) line-intensity signal targeted by the CO Mapping Array Project (COMAP) Pathfinder in the context of its early science results. Our fiducial model, relating dark matter halo properties to CO luminosities, informs parameter priors with empirical models of the galaxy-halo connection and previous CO(1-0) observations. The Pathfinder early science data spanning wavenumbers $k=0.051$-$0.62$Mpc${}^{-1}$ represent the first direct 3D constraint on the clustering component of the CO(1-0) power spectrum. Our 95% upper limit on the redshift-space clustering amplitude $A_{\mathrm{clust}}\lesssim 70\mu$K${}^2$ greatly improves on the indirect upper limit of $420\mu$K${}^2$ reported from the CO Power Spectrum Survey (COPSS) measurement at $k\sim 1$Mpc${}^{-1}$. The COMAP limit excludes a subset of models from previous literature, and constrains interpretation of the COPSS results, demonstrating the complementary nature of COMAP and interferometric CO surveys. Using line bias expectations from our priors, we also constrain the squared mean line intensity-bias product, $⟨Tb{⟩}^2\lesssim 50\mu$K${}^2$, and the cosmic molecular gas density, ${\rho }_{\text{H2}}<2.5\times 10^8{M}_{\odot }$Mpc${}^{-3}$ (95% upper limits). Based on early instrument performance and our current CO signal estimates, we forecast that the five-year Pathfinder campaign will detect the CO power spectrum with overall signal-to-noise of 9-17. Between then and now, we also expect to detect the CO-galaxy cross-spectrum using overlapping galaxy survey data, enabling enhanced inferences of cosmic star-formation and galaxy-evolution history.

Paper 5 of 7 in series. 17 pages + appendix and bibliography (30 pages total); 15 figures, 6 tables; accepted for publication in ApJ; v3 reflects the accepted version with minor changes and additions to text

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Cited by in corpus (30)

• COMAP Early Science: I. Overview
• COMAP Early Science: VII. Prospects for CO Intensity Mapping at Reionization
• [CII] line intensity mapping the epoch of reionization with the Prime-Cam on FYST
• COMAP Early Science: IV. Power Spectrum Methodology and Results
• LIMFAST. II. Line Intensity Mapping as a Probe of High-Redshift Galaxy Formation
• COMAP Early Science: II. Pathfinder Instrument
• COMAP Early Science: III. CO Data Processing
• Revisiting the [C II]${}_{158\mu \text{m}}$ line-intensity mapping power spectrum from the EoR using non-uniform line-luminosity scatter
• A multi-tracer empirically-driven approach to line-intensity mapping lightcones
• Unveiling cosmological information on small scales with line intensity mapping
• Synergizing 21 cm and sub-millimetre surveys during reionization: new empirical insights
• Exploration of 3D wavelet scattering transform coefficients for line-intensity mapping measurements
• The deconvolved distribution estimator: enhancing reionisation-era CO line-intensity mapping analyses with a cross-correlation analogue for one-point statistics
• Foreground Removal of CO Intensity Mapping Using Deep Learning
• COMAP Pathfinder -- Season 2 results I. Improved data selection and processing
• Characteristic Functions for Cosmological Cross-Correlations
• SIMPLE: Simple Intensity Map Producer for Line Emission
• Boosting Line Intensity Map Signal-to-Noise with the Ly-$\alpha$ Forest Cross-Correlation
• Towards Accurate Modeling of Line-Intensity Mapping One-Point Statistics: Including Extended Profiles
• Constraining Cosmology With the CMB $\times$ LIM-Nulling Convergence
• COMAP Pathfinder -- Season 2 results II. Updated constraints on the CO(1-0) power spectrum
• Leveraging cross-correlations and linear covariance-based filtering for line-intensity map reconstructions at linear scales
• Three-Dimensional Stacking as a Line Intensity Mapping Statistic
• COMAP Pathfinder -- Season 2 results III. Implications for cosmic molecular gas content at "Cosmic Half-past Eleven"
• [CII] luminosity models and large-scale image cubes based on COSMOS 2020 and ALPINE-ALMA [CII] data back to the epoch of reionisation
• Reionization relics in the cross-correlation between the Ly$\alpha$ forest and 21 cm intensity mapping in the post-reionization era
• Constraining the halo-ISM connection through multi-transition carbon monoxide line-intensity mapping
• Direct correlation of line intensity mapping and CMB lensing from evolution along the lightcone
• COMAP Pathfinder -- Season 2 results IV. A stack on eBOSS/DESI quasars
• Comparison of Cross-Correlation Methods for Line Intensity Mapping