COMAP Early Science: IV. Power Spectrum Methodology and Results

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 $k=0.051-0.62{\mathrm{Mpc}}^{-1}$ we estimate $P_{\mathrm{CO}}(k)=-2.7\pm 1.7\times 10^4\mu {\text{K}}^2{\mathrm{Mpc}}^3$, the first direct 3D constraint on the clustering component of the CO(1-0) power spectrum in the literature.

Paper 4 of 7 in series. 18 pages, 11 figures, as accepted in ApJ

References in corpus (21)

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Cited by in corpus (20)

• COMAP Early Science: I. Overview
• COMAP Early Science: V. Constraints and Forecasts at $z\sim 3$
• COMAP Early Science: VII. Prospects for CO Intensity Mapping at Reionization
• 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
• Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]
• Exploration of 3D wavelet scattering transform coefficients for line-intensity mapping measurements
• Foreground Removal of CO Intensity Mapping Using Deep Learning
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• Characteristic Functions for Cosmological Cross-Correlations
• COMAP Pathfinder -- Season 2 results I. Improved data selection and processing
• Boosting Line Intensity Map Signal-to-Noise with the Ly-$\alpha$ Forest Cross-Correlation
• COMAP Pathfinder -- Season 2 results II. Updated constraints on the CO(1-0) power spectrum
• A Forecast for Large Scale Structure Constraints on Horndeski Gravity with Line Intensity Mapping
• Probing the Epoch of Reionization using synergies of line intensity mapping
• Leveraging cross-correlations and linear covariance-based filtering for line-intensity map reconstructions at linear scales
• COMAP Pathfinder -- Season 2 results III. Implications for cosmic molecular gas content at "Cosmic Half-past Eleven"
• Direct correlation of line intensity mapping and CMB lensing from evolution along the lightcone
• Constraining the [CII] luminosity function from the power spectrum of line-intensity maps at redshift 3.6