Towards Optimal Foreground Mitigation Strategies for Interferometric HI Intensity Mapping in the Low-Redshift Universe

Abstract

We conduct the first case study towards developing optimal foreground mitigation strategies for neutral hydrogen (HI) intensity mapping using radio interferometers at low redshifts. A pipeline for simulation, foreground mitigation and power spectrum estimation is built, which can be used for ongoing and future surveys using MeerKAT and Square Kilometre Array Observatory (SKAO). It simulates realistic sky signals to generate visibility data given instrument and observation specifications, which is subsequently used to perform foreground mitigation and power spectrum estimation. A quadratic estimator formalism is developed to estimate the temperature power spectrum in visibility space. Using MeerKAT telescope specifications for observations in the redshift range z~0.25-0.30 corresponding to the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey, we present a case study where we compare different approaches of foreground mitigation. We find that component separation in visibility space provides a more accurate estimation of HI clustering comparing to foreground avoidance, with the uncertainties being 30 per cent smaller. Power spectrum estimation from image is found to be less robust with larger bias and more information loss when compared to estimation in visibility. We conclude that for z~0.25-0.30, the MIGHTEE survey will be capable of measuring the HI power spectrum from k~0.5 Mpc${}^{-1}$ to k~10 Mpc${}^{-1}$ with high accuracy. We are the first to show that, at low redshift, component separation in visibility space suppresses foreground contamination at large line-of-sight scales, allowing measurement of HI power spectrum closer to the foreground wedge, crucial for data analysis towards future detections.

arXiv comment20 pages, 19 figures. Updated to match the published version in MNRAS

References in corpus (98)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• The Structure of Cold Dark Matter Halos
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Efficient Computation of CMB anisotropies in closed FRW models
• Baryonic Features in the Matter Transfer Function
• Halo Models of Large Scale Structure
• The Cosmic Evolution Survey (COSMOS) -- Overview
• Toward a halo mass function for precision cosmology: the limits of universality
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory
• The Large Scale Bias of Dark Matter Halos: Numerical Calibration and Model Tests
• Theoretical Models of the Halo Occupation Distribution: Separating Central and Satellite Galaxies
• 21-cm Tomography of the Intergalactic Medium at High Redshift
• Hydrogen Epoch of Reionization Array (HERA)
• A Full-Sky H-alpha Template for Microwave Foreground Prediction
• The Cosmological Analysis of the SDSS/BOSS data from the Effective Field Theory of Large-Scale Structure
• How to measure CMB power spectra without losing information
• Baryon Acoustic Oscillation Intensity Mapping as a Test of Dark Energy
• Measurement of 21 cm brightness fluctuations at z ~ 0.8 in cross-correlation
• Late-time cosmology with 21cm intensity mapping experiments
• A Per-Baseline, Delay-Spectrum Technique for Accessing the 21cm Cosmic Reionization Signature
• The non-coplanar baselines effect in radio interferometry: The W-Projection algorithm
• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• Cosmology with Phase 1 of the Square Kilometre Array; Red Book 2018: Technical specifications and performance forecasts
• Multifrequency analysis of 21 cm fluctuations from the Era of Reionization
• 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
• New Limits on 21cm EoR From PAPER-32 Consistent with an X-Ray Heated IGM at z=7.7
• Determination of z~0.8 neutral hydrogen fluctuations using the 21 cm intensity mapping auto-correlation
• Toward Epoch of Reionization Measurements with Wide-Field Radio Observations
• HI intensity mapping : a single dish approach
• Data Analysis for Precision 21 cm Cosmology
• Towards a free-free template for CMB foregrounds
• Radio Foregrounds for the 21cm Tomography of the Neutral Intergalactic Medium at High Redshifts
• The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• A Sensitivity and Array-Configuration Study for Measuring the Power Spectrum of 21cm Emission from Reionization
• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• Ingredients for 21cm intensity mapping
• An Improved Model of Diffuse Galactic Radio Emission from 10 MHz to 5 THz
• Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data
• Calibration Requirements for Detecting the 21 cm Epoch of Reionization Power Spectrum and Implications for the SKA
• Foreground Contamination in Interferometric Measurements of the Redshifted 21 cm Power Spectrum
• A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
• Foreground Removal using FastICA: A Showcase of LOFAR-EoR
• Lack of clustering in low-redshift 21-cm intensity maps cross-correlated with 2dF galaxy densities
• Foregrounds in Wide-Field Redshifted 21 cm Power Spectra
• The EAGLE simulations: atomic hydrogen associated with galaxies
• The VLA-VIRMOS Deep Field I. Radio observations probing the microJy source population
• Neutral hydrogen surveys for high redshift galaxy clusters and proto-clusters
• Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations
• The 1.28 GHz MeerKAT DEEP2 Image
• CHIPS: The Cosmological HI Power Spectrum Estimator
• Empirical Covariance Modeling for 21 cm Power Spectrum Estimation: A Method Demonstration and New Limits from Early Murchison Widefield Array 128-Tile Data
• Statistical 21-cm Signal Separation via Gaussian Process Regression Analysis
• Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
• Tracing HI Beyond the Local Universe
• HI constraints from the cross-correlation of eBOSS galaxies and Green Bank Telescope intensity maps
• Towards Optimal Measurement of Power Spectra I: Minimum Variance Pair Weighting and the Fisher Matrix
• Confirmation of Wide-Field Signatures in Redshifted 21 cm Power Spectra
• Will point sources spoil 21 cm tomography?
• A Fast Gridded Method for the Estimation of the Power Spectrum of the CMB from Interferometer Data with Application to the Cosmic Background Imager
• Effects of Antenna Beam Chromaticity on Redshifted 21~cm Power Spectrum and Implications for Hydrogen Epoch of Reionization Array
• Fast simulations for intensity mapping experiments
• Decorrelating the Power Spectrum of Galaxies
• Simulations for single-dish intensity mapping experiments
• Characterizing Signal Loss in the 21 cm Reionization Power Spectrum: A Revised Study of PAPER-64
• 21cm foregrounds and polarization leakage: a user's guide on cleaning and mitigation strategies
• Understanding the Diversity of 21 cm Cosmology Analyses
• The atomic Hydrogen content of the post-reionization Universe
• The 21cm Power Spectrum After Reionization
• Primary beam effects of radio astronomy antennas -- II. Modelling the MeerKAT L-band beam
• Visibility based angular power spectrum estimation in low frequency radio interferometric observations
• Comparing Foreground Removal Techniques for Recovery of the LOFAR-EoR 21cm Power Spectrum
• Multi-tracer intensity mapping: Cross-correlations, Line noise & Decorrelation
• Gaussian Process Foreground Subtraction and Power Spectrum Estimation for 21 cm Cosmology
• The clustering and bias of radio-selected AGN and star-forming galaxies in the COSMOS field
• TheHaloMod: An online calculator for the halo model
• Cosmological parameter forecasts for HI intensity mapping experiments using the angular power spectrum
• Forecast for FAST: from Galaxies Survey to Intensity Mapping
• Foreground removal for Square Kilometre Array observations of the Epoch of Reionization with the Correlated Component Analysis
• Source Counts Spanning Eight Decades of Flux Density at 1.4 GHz
• Intensity Mapping Cross-Correlations: Connecting the Largest Scales to Galaxy Evolution
• Intensity mapping cross-correlations II: HI halo models including shot noise
• Powerbox: A Python package for creating structured fields with isotropic power spectra
• One- and Two-point Source Statistics from the LOFAR Two-metre Sky Survey First Data Release
• Spectral index of the Galactic foreground emission in the 50-87 MHz range
• A model of spectral line broadening in signal forecasts for line-intensity mapping experiments
• Impact of astrophysics on cosmology forecasts for 21 cm surveys
• Extracting HI Astrophysics from Interferometric Intensity Mapping
• An Improved Statistical Point-Source Foreground Model for the Epoch of Reionization
• Methods of Error Estimation for Delay Power Spectra in $21\text{cm}$ Cosmology
• The Impact of Realistic Foreground and Instrument Models on 21cm Epoch of Reionization Experiments
• HI intensity mapping with the MIGHTEE survey: power spectrum estimates
• An analytical method to simulate the HI 21-cm visibility signal for intensity mapping experiments
• Contribution of Galactic free-free emission to the foreground for EoR signal in SKA experiments
• Simulated Predictions for HI at $z=3.35$ with the Ooty Wide Field Array (OWFA) -- II: Foreground Avoidance

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• The foreground transfer function for HI intensity mapping signal reconstruction: MeerKLASS and precision cosmology applications
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• Detecting the HI Power Spectrum in the Post-Reionization Universe with SKA-Low
• Emission-line Stacking of 21cm Intensity Maps with MeerKLASS: Inference Pipeline and Application to the L-band Deep-field Data
• HI Intensity Mapping with the MIGHTEE Survey: First Results of the HI Power Spectrum
• Power spectrum multipoles and clustering wedges during the Epoch of Reionization