Strategy for mitigation of systematics for EoR experiments with the Murchison Widefield Array

Abstract

Observations of the 21 cm signal face significant challenges due to bright astrophysical foregrounds that are several orders of magnitude higher than the brightness of the hydrogen line, along with various systematics. Successful 21 cm experiments require accurate calibration and foreground mitigation. Errors introduced during the calibration process such as systematics, can disrupt the intrinsic frequency smoothness of the foregrounds, leading to power leakage into the Epoch of Reionisation (EoR) window. Therefore, it is essential to develop strategies to effectively address these challenges. In this work, we adopt a stringent approach to identify and address suspected systematics, including malfunctioning antennas, frequency channels corrupted by radio frequency interference (RFI), and other dominant effects. We implement a statistical framework that utilises various data products from the data processing pipeline to derive specific criteria and filters. These criteria and filters are applied at intermediate stages to mitigate systematic propagation from the early stages of data processing. Our analysis focuses on observations from the Murchison Widefield Array (MWA) Phase I configuration. Out of the observations processed by the pipeline, our approach selects 18%, totalling 58 hours, that exhibit fewer systematic effects. The successful selection of observations with reduced systematic dominance enhances our confidence in achieving 21 cm measurements.

18 pages, 17 figures, 2 tables (accepted for publication in PASA)

References in corpus (45)

• LOFAR: The LOw-Frequency ARray
• The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies
• Hydrogen Epoch of Reionization Array (HERA)
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• A morphological algorithm for improving radio-frequency interference detection
• GLEAM: The GaLactic and Extragalactic All-sky MWA survey
• The Epoch of Reionization Window: I. Mathematical Formalism
• Toward Epoch of Reionization Measurements with Wide-Field Radio Observations
• The Phase II Murchison Widefield Array: Design Overview
• 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 Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• Calibration Requirements for Detecting the 21 cm Epoch of Reionization Power Spectrum and Implications for the SKA
• The GMRT-EoR Experiment: A new upper limit on the neutral hydrogen power spectrum at z~8.6
• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• Real-Time Calibration of the Murchison Widefield Array
• First Season MWA EoR Power Spectrum Results at Redshift 7
• HERA Phase I Limits on the Cosmic 21-cm Signal: Constraints on Astrophysics and Cosmology During the Epoch of Reionization
• The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation
• Improving the Epoch of Reionization Power Spectrum Results from Murchison Widefield Array Season 1 Observations
• Improving Foreground Subtraction in Statistical Observations of 21 cm Emission from the Epoch of Reionization
• CHIPS: The Cosmological HI Power Spectrum Estimator
• 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
• Fast Holographic Deconvolution: a new technique for precision radio interferometry
• A 189 MHz, 2400 square degree polarization survey with the Murchison Widefield Array 32-element prototype
• First Season MWA Phase II EoR Power Spectrum Results at Redshift 7
• Characterisation of the ionosphere above the Murchison Radio Observatory using the Murchison Widefield Array
• Mitigating Internal Instrument Coupling II: A Method Demonstration with the Hydrogen Epoch of Reionization Array
• Understanding the Diversity of 21 cm Cosmology Analyses
• Absolving the SSINS of Precision Interferometric Radio Data: A New Technique for Mitigating Faint Radio Frequency Interference
• Calibration and Stokes Imaging with Full Embedded Element Primary Beam Model for the Murchison Widefield Array
• Interferometric imaging with the 32 element Murchison Wide-field Array
• Subtraction of point sources from interferometric radio images through an algebraic forward modeling scheme
• The 21-cm Line as a Probe of Reionization
• Array Element Coupling in Radio Interferometry I: A Semi-Analytic Approach
• New Limits on Polarized Power Spectra at 126 and 164 MHz: Relevance to Epoch of Reionization Measurements
• A high resolution foreground model for the MWA EoR1 field: model and implications for EoR power spectrum analysis
• Constraining Polarized Foregrounds for EOR Experiments II: Polarization Leakage Simulations in the Avoidance Scheme
• New EoR Power Spectrum Limits From MWA Phase II Using the Delay Spectrum Method and Novel Systematic Rejection
• Measuring HERA's primary beam in-situ: methodology and first results
• Evidence of Ultra-faint Radio Frequency Interference in Deep 21~cm Epoch of Reionization Power Spectra with the Murchison Widefield Array
• Beamforming Errors in Murchison Widefield Array Phased Array Antennas and their effects on Epoch of Reionization Science
• Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array
• Verifying the Australian MWA EoR pipeline I: 21-cm sky model and correlated measurement density

Cited by in corpus (1)

• Altitude Estimation of Radio Frequency Interference Sources via Interferometric Near Field Corrections