Unlocking Sensitivity for Visibility-based Estimators of the 21 cm Reionization Power Spectrum

Abstract

Radio interferometers designed to measure the cosmological 21 cm power spectrum require high sensitivity. Several modern low-frequency interferometers feature drift-scan antennas placed on a regular grid to maximize the number of instantaneously coherent (redundant) measurements. However, even for such maximum-redundancy arrays, significant sensitivity comes through partial coherence between baselines. Current visibility-based power-spectrum pipelines, though shown to ease control of systematics, lack the ability to make use of this partial redundancy. We introduce a method to leverage partial redundancy in such power-spectrum pipelines for drift-scan arrays. Our method cross-multiplies baseline pairs at a time lag and quantifies the sensitivity contributions of each pair of baselines. Using the configurations and beams of the 128-element Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER-128) and staged deployments of the Hydrogen Epoch of Reionization Array, we illustrate how our method applies to different arrays and predict the sensitivity improvements associated with pairing partially coherent baselines. As the number of antennas increases, we find partial redundancy to be of increasing importance in unlocking the full sensitivity of upcoming arrays.

15 pages, 10 figures; Replaced with accepted ApJ version (some clarifying comments; no changes to results)

References in corpus (20)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Observational constraints on Cosmic Reionization
• Hydrogen Epoch of Reionization Array (HERA)
• Late-time cosmology with 21cm intensity mapping experiments
• Upper limits on the 21-cm Epoch of Reionization power spectrum from one night with LOFAR
• How accurately can 21 cm tomography constrain cosmology?
• The Epoch of Reionization Window: I. Mathematical Formalism
• Studying Reionization with Ly-alpha Emitters
• A measurement of secondary cosmic microwave background anisotropies from the 2500-square-degree SPT-SZ survey
• The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• First Season MWA EoR Power Spectrum Results at Redshift 7
• First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ~ 7
• Detecting patchy reionization in the CMB
• Visibility based angular power spectrum estimation in low frequency radio interferometric observations
• Spherical Harmonic Analyses of Intensity Mapping Power Spectra
• The visibility based Tapered Gridded Estimator (TGE) for the redshifted 21-cm power spectrum
• Tapering the sky response for angular power spectrum estimation from low-frequency radio-interferometric data
• Constraining Polarized Foregrounds for EoR Experiments I: 2D Power Spectra from the PAPER-32 Imaging Array
• Delay Spectrum with Phase-Tracking Arrays: Extracting the HI power spectrum from the Epoch of Reionization
• Comparison of observing modes for statistical estimation of the 21cm signal from the Epoch of Reionisation

Cited by in corpus (7)

• Data Analysis for Precision 21 cm Cosmology
• Understanding the Diversity of 21 cm Cosmology Analyses
• DAYENU: A Simple Filter of Smooth Foregrounds for Intensity Mapping Power Spectra
• 21cmEMU: an emulator of 21cmFAST summary observables
• Foreground modelling via Gaussian process regression: an application to HERA data
• Fundamental uncertainty levels of 21cm power spectra from a delay analysis
• Forecasts and Statistical Insights for Line Intensity Mapping Cross-Correlations: A Case Study with 21cm x [CII]