Foreground modelling via Gaussian process regression: an application to HERA data

Abstract

The key challenge in the observation of the redshifted 21-cm signal from cosmic reionization is its separation from the much brighter foreground emission. Such separation relies on the different spectral properties of the two components, although, in real life, the foreground intrinsic spectrum is often corrupted by the instrumental response, inducing systematic effects that can further jeopardize the measurement of the 21-cm signal. In this paper, we use Gaussian Process Regression to model both foreground emission and instrumental systematics in $\sim 2$ hours of data from the Hydrogen Epoch of Reionization Array. We find that a simple co-variance model with three components matches the data well, giving a residual power spectrum with white noise properties. These consist of an "intrinsic" and instrumentally corrupted component with a coherence-scale of 20 MHz and 2.4 MHz respectively (dominating the line of sight power spectrum over scales $k_{\parallel }\le 0.2$ h cMpc${}^{-1}$) and a baseline dependent periodic signal with a period of $\sim 1$ MHz (dominating over $k_{\parallel }\sim 0.4-0.8$h cMpc${}^{-1}$) which should be distinguishable from the 21-cm EoR signal whose typical coherence-scales is $\sim 0.8$ MHz.

15 pages, 15 figures, 1 table, Accepted to MNRAS

References in corpus (84)

• emcee: The MCMC Hammer
• Planck 2015 results. XIII. Cosmological parameters
• An absorption profile centred at 78 megahertz in the sky-averaged spectrum
• 21-cm cosmology
• 21cmFAST: A Fast, Semi-Numerical Simulation of the High-Redshift 21-cm Signal
• Hydrogen Epoch of Reionization Array (HERA)
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• Reionization and Cosmology with 21 cm Fluctuations
• Efficient Simulations of Early Structure Formation and Reionization
• 21 Centimeter Fluctuations from Cosmic Gas at High Redshifts
• Bright Source Subtraction Requirements For Redshifted 21 cm Measurements
• What Next-Generation 21 cm Power Spectrum Measurements Can Teach Us About the Epoch of Reionization
• Reionization and the Cosmic Dawn with the Square Kilometre Array
• A Per-Baseline, Delay-Spectrum Technique for Accessing the 21cm Cosmic Reionization Signature
• Four Fundamental Foreground Power Spectrum Shapes for 21 cm Cosmology Observations
• Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at $\mathbf{z}\approx 9.1$ from LOFAR
• 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
• 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
• Foreground simulations for the LOFAR - Epoch of Reionization Experiment
• Distance measures in cosmology
• PAPER-64 Constraints on Reionization: The 21cm Power Spectrum at z=8.4
• Imaging the Epoch of Reionization: limitations from foreground confusion and imaging algorithms
• How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641?
• A lower limit of dz > 0.06 for the duration of the reionization epoch
• A Sensitivity and Array-Configuration Study for Measuring the Power Spectrum of 21cm Emission from Reionization
• The impact of point source subtraction residuals on 21 cm Epoch of Reionization estimation
• The observable signature of late heating of the Universe during cosmic reionization
• 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
• Foregrounds for observations of the cosmological 21 cm line: I. First Westerbork measurements of Galactic emission at 150 MHz in a low latitude field
• Foreground Contamination in Interferometric Measurements of the Redshifted 21 cm Power Spectrum
• A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
• First Season MWA EoR Power Spectrum Results at Redshift 7
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• A study of fundamental limitations to statistical detection of redshifted HI from the epoch of reionization
• Fast Large Volume Simulations of the 21 cm Signal from the Reionization and pre-Reionization Epochs
• Foregrounds in Wide-Field Redshifted 21 cm Power Spectra
• Initial deep LOFAR observations of Epoch of Reionization windows: I. The North Celestial Pole
• The EDGES 21 cm Anomaly and Properties of Dark Matter
• A simplified, lossless re-analysis of PAPER-64
• The Scale of the Problem : Recovering Images of Reionization with GMCA
• Improving Foreground Subtraction in Statistical Observations of 21 cm Emission from the Epoch of Reionization
• 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
• Bayesian constraints on the global 21-cm signal from the Cosmic Dawn
• The Epoch of Reionization
• Foregrounds for observations of the cosmological 21 cm line: II. Westerbork observations of the fields around 3C196 and the North Celestial Pole
• The Impact of Modeling Errors on Interferometer Calibration for 21 cm Power Spectra
• Systematic biases in low frequency radio interferometric data due to calibration: the LOFAR EoR case
• The first power spectrum limit on the 21-cm signal of neutral hydrogen during the Cosmic Dawn at z=20-25 from LOFAR
• The impact of the supersonic baryon-dark matter velocity difference on the z~20 21cm background
• Non-parametric foreground subtraction for 21cm epoch of reionization experiments
• HI Fluctuations at Large Redshifts: I--Visibility correlation
• Fundamental Limitations on the Calibration of Redundant 21 cm Cosmology Instruments and Implications for HERA and the SKA
• Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
• Mitigating Internal Instrument Coupling for 21 cm Cosmology I: Temporal and Spectral Modeling in Simulations
• Improved foreground removal in GMRT 610 MHz observations towards redshifted 21-cm tomography
• Redundant Array Configurations for 21 cm Cosmology
• Constraining the redshifted 21-cm signal with the unresolved soft X-ray background
• The Impact of Foregrounds on Redshift Space Distortion Measurements With the Highly-Redshifted 21 cm Line
• Spectroscopic investigation of a reionized galaxy overdensity at z=7
• Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
• SARAS measurement of the Radio Background at long wavelengths
• Scintillation noise power spectrum and its impact on high redshift 21-cm observations
• Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum
• HI 21cm Cosmology and the Bi-spectrum: Closure Diagnostics in Massively Redundant Interferometric Arrays
• DAYENU: A Simple Filter of Smooth Foregrounds for Intensity Mapping Power Spectra
• The visibility based Tapered Gridded Estimator (TGE) for the redshifted 21-cm power spectrum
• Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure
• HI Epoch of Reionization Arrays
• Polarised foreground removal at low radio frequencies using rotation measure synthesis: uncovering the signature of hydrogen reionisation
• Foreground removal for Square Kilometre Array observations of the Epoch of Reionization with the Correlated Component Analysis
• Improved 21 cm Epoch Of Reionization Power Spectrum Measurements with a Hybrid Foreground Subtraction and Avoidance Technique
• The wedge bias in reionization 21-cm power spectrum measurements
• Constraining Polarized Foregrounds for EOR Experiments II: Polarization Leakage Simulations in the Avoidance Scheme
• Ionospheric Power-Spectrum Tomography in Radio Interferometry
• Probing the first galaxies with the SKA
• Detecting Cosmic Reionization using Bi-Spectrum Phase
• Fundamental uncertainty levels of 21cm power spectra from a delay analysis
• Redundant interferometric calibration as a complex optimization problem
• Unlocking Sensitivity for Visibility-based Estimators of the 21 cm Reionization Power Spectrum
• Lifetimes and Oscillator Strengths for Ultraviolet Transitions in Neutral Chlorine

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• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• Gaussian Process Foreground Subtraction and Power Spectrum Estimation for 21 cm Cosmology
• The AARTFAAC Cosmic Explorer: observations of the 21-cm power spectrum in the EDGES absorption trough
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• The Second Radio Synchrotron Background Workshop: Conference Summary and Report
• Demonstrating the Tapered Gridded Estimator (TGE) for the Cosmological HI 21-cm Power Spectrum using $150\mathrm{MHz}$ GMRT observations
• Statistical recovery of 21cm visibilities and their power spectra with Gaussian constrained realisations and Gibbs sampling
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• A Semi-blind PCA-based Foreground Subtraction Method for 21 cm Intensity Mapping
• Machine Learning and Cosmology
• All Sky Modelling Requirements for Bayesian 21 cm Power Spectrum Estimation with BayesEoR
• SKA-Low Intensity Mapping Pathfinder Updates: Deeper 21 cm Power Spectrum Limits from Improved Analysis Frameworks
• Characterization Of Inpaint Residuals In Interferometric Measurements of the Epoch Of Reionization
• Spectral modelling of Cygnus A between 110 and 250 MHz. Impact on the LOFAR 21-cm signal power spectrum
• Cross-Correlation Forecast of CSST Spectroscopic Galaxy and MeerKAT Neutral Hydrogen Intensity Mapping Surveys
• The Tracking Tapered Gridded Estimator (TTGE) for the power spectrum from drift scan observations
• Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array
• Combined lensed estimator to probe the post reionization H I power spectrum
• Photometry on Structured Backgrounds: Local Pixelwise Infilling by Regression
• Mitigating gain calibration errors from EoR observations with SKA1-Low AA*
• Mitigating incoherent excess variance in high-redshift 21 cm observations with multi-output cross-Gaussian process regression