Exploring One-point Statistics in HERA Phase I Data: Effects of Foregrounds and Systematics on Measuring One-Point Statistics

Abstract

Measuring one-point statistics in redshifted 21 cm intensity maps offers an opportunity to explore non-Gaussian features of the early universe. We assess the impact of instrumental effects on measurements made with the Hydrogen Epoch of Reionization Array (HERA) by forward modeling observational and simulation data. Using HERA Phase I observations over 94 nights, we examine the second (m2, variance) and third (m3) moments of images. We employ the DAYENU-filtering method for foreground removal and reduce simulated foreground residuals to 10% of the 21 cm signal residuals. In noiseless cosmological simulations, the amplitudes of one-point statistics measurements are significantly reduced by the instrument response and further reduced by wedge-filtering. Analyses with wedge-filtered observational data, along with expected noise simulations, show that systematics alter the probability distribution of the map pixels. Likelihood analysis based on the observational data shows m2 measurements disfavor the cold reionization model characterized by inefficient X-ray heating, in line with other power spectra measurements. Small signals in m3 due to the instrument response of the Phase I observation and wedge-filtering make it challenging to use these non-Gaussian statistics to explore model parameters. Forecasts with the full HERA array predict high signal-to-noise ratios for m2, m3, and S3 assuming no foregrounds, but wedge-filtering drastically reduces these ratios. This work demonstrates conclusively that a comprehensive understanding of instrumental effects on m2 and m3 is essential for their use as a cosmological probe, given their dependence on the underlying model.

29 pages, 18 figures

References in corpus (93)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• LOFAR: The LOw-Frequency ARray
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies
• 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
• Multi-Scale CLEAN deconvolution of radio synthesis images
• The Precision Array for Probing the Epoch of Reionization: 8 Station Results
• 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
• A simulation calibrated limit on the HI power spectrum from the GMRT Epoch of Reionization experiment
• 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
• 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
• 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
• Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal
• Imaging the Epoch of Reionization: limitations from foreground confusion and imaging algorithms
• Deep multi-redshift limits on Epoch of Reionisation 21cm Power Spectra from Four Seasons of Murchison Widefield Array Observations
• The impact of point source subtraction residuals on 21 cm Epoch of Reionization estimation
• First Results from HERA Phase I: Upper Limits on the Epoch of Reionization 21 cm Power Spectrum
• 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
• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• First Season MWA EoR Power Spectrum Results at Redshift 7
• A study of fundamental limitations to statistical detection of redshifted HI from the epoch of reionization
• HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
• Blind foreground subtraction for intensity mapping experiments
• 21cmFAST v3: A Python-integrated C code forgenerating 3D realizations of the cosmic 21cm signal
• A simplified, lossless re-analysis of PAPER-64
• Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations
• Statistical 21-cm Signal Separation via Gaussian Process Regression Analysis
• Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum
• Fast Holographic Deconvolution: a new technique for precision radio interferometry
• HI intensity mapping with MeerKAT: power spectrum detection in cross-correlation with WiggleZ galaxies
• A 189 MHz, 2400 square degree polarization survey with the Murchison Widefield Array 32-element prototype
• MITEoR: A Scalable Interferometer for Precision 21 cm Cosmology
• Reionization and Beyond: detecting the peaks of the cosmological 21cm signal
• 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
• Effects of Antenna Beam Chromaticity on Redshifted 21~cm Power Spectrum and Implications for Hydrogen Epoch of Reionization Array
• Redundant Array Configurations for 21 cm Cosmology
• Characterizing Signal Loss in the 21 cm Reionization Power Spectrum: A Revised Study of PAPER-64
• SKAO HI Intensity Mapping: Blind Foreground Subtraction Challenge
• Mitigating the Effects of Antenna-to-Antenna Variation on Redundant-Baseline Calibration for 21 cm Cosmology
• Image Domain Gridding: a fast method for convolutional resampling of visibilities
• The 21cm bispectrum as a probe of non-Gaussianities due to X-ray heating
• 21cm-line bispectrum as method to probe Cosmic Dawn and Epoch of Reionization
• Understanding the Diversity of 21 cm Cosmology Analyses
• Biased Reionisation and Non-Gaussianity in Redshifted 21cm Intensity Maps of the Reionisation Epoch
• The 21cm bispectrum during reionization: a tracer of the ionization topology
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey II: Galactic Plane $345^{\circ }<l<67^{\circ }$, $180^{\circ }<l<240^{\circ }$
• Detection and extraction of signals from the epoch of reionization using higher order one-point statistics
• Comparing Redundant and Sky Model Based Interferometric Calibration: A First Look with Phase II of the MWA
• Redundant-Baseline Calibration of the Hydrogen Epoch of Reionization Array
• Distinguishing models of reionization using future radio observations of 21-cm 1-point statistics
• Gaussian Process Foreground Subtraction and Power Spectrum Estimation for 21 cm Cosmology
• Sensitivity for 21cm Bispectrum from Epoch of Reionization
• The impact of spin temperature fluctuations on the 21-cm moments
• Recovering the Wedge Modes Lost to 21-cm Foregrounds
• Mapmaking for Precision 21 cm Cosmology
• Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum
• Absolute Calibration Strategies for the Hydrogen Epoch of Reionization Array and Their Impact on the 21 cm Power Spectrum
• DAYENU: A Simple Filter of Smooth Foregrounds for Intensity Mapping Power Spectra
• Machine learning astrophysics from 21 cm lightcones: impact of network architectures and signal contamination
• Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure
• Studying 21cm power spectrum with one-point statistics
• Redshifted 21-cm Bispectrum I: Impact of the Redshift Space Distortions on the Signal from the Epoch of Reionization
• Gaussian Process Regression for foreground removal in HI intensity mapping experiments
• Exploring the cosmic 21-cm signal from the Epoch of Reionisation using the Wavelet Scattering Transform
• Redshifted 21-cm bispectrum II: Impact of the spin temperature fluctuations and redshift space distortions on the signal from the Cosmic Dawn
• Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
• Precision requirements for interferometric gridding in 21-cm power spectrum analysis
• Constraining Primordial Non-Gaussianity with Post-reconstructed Galaxy Bispectrum in Redshift Space
• Design of the New Wideband Vivaldi Feed for the HERA Radio-Telescope Phase II
• The effect of baseline layouts on the EoR foreground wedge: a semi-analytical approach
• The HERA-19 Commissioning Array: Direction Dependent Effects
• The Epoch of Reionization 21-cm Bispectrum: The impact of light-cone effects and detectability
• The Impact of Beam Variations on Power Spectrum Estimation for 21-cm Cosmology I: Simulations of Foreground Contamination for HERA
• Expected constraints on models of the epoch of reionization with the variance and skewness in redshifted 21cm-line fluctuations
• Detecting the non-Gaussianity of the 21-cm signal during reionisation with the Wavelet Scattering Transform
• Statistics of 21-cm Fluctuations in Cosmic Reionization Simulations: PDFs and Difference PDFs
• Constraints on the state of the IGM at $z\sim 8-10$ using redshifted 21-cm observations with LOFAR
• Sensitivity of the Hydrogen Epoch of Reionization Array and its Build-out Stages to One-point Statistics from Redshifted 21 cm Observations
• Wavelet Based Statistics for Enhanced 21cm EoR Parameter Constraints
• The 21-cm bispectrum from neutral hydrogen islands at z < 6
• Direct Optimal Mapping for 21cm Cosmology: A Demonstration with the Hydrogen Epoch of Reionization Array
• Impact of the Epoch of Reionization sources on the 21-cm bispectrum
• Measurements of one-point statistics in 21 cm intensity maps via foreground avoidance strategy
• The Statistics of Negative Power Spectrum Systematics in some 21 cm Analyses