The precision and accuracy of early Epoch of Reionization foreground models: comparing MWA and PAPER 32-antenna source catalogs

Abstract

As observations of the Epoch of Reionization (EoR) in redshifted 21cm emission begin, we asses the accuracy of the early catalog results from the Precision Array for Probing the Epoch of Reionization (PAPER) and the Murchison Widefield Array. The MWA EoR approach derives much of its sensitivity from subtracting foregrounds to <1% precision while the PAPER approach relies on the stability and symmetry of the primary beam. Both require an accurate flux calibration to set the amplitude of the measured power spectrum. The two instruments are very similar in resolution, sensitivity, sky coverage and spectral range and have produced catalogs from nearly contemporaneous data. We use a Bayesian MCMC fitting method to estimate that the two instruments are on the same flux scale to within 20% and find that the images are mostly in good agreement. We then investigate the source of the errors by comparing two overlapping MWA facets where we find that the differences are primarily related to an inaccurate model of the primary beam but also correlated errors in bright sources due to CLEAN. We conclude with suggestions for mitigating and better characterizing these effects.

10 pages, 10 figures, submitted to ApJ

References in corpus (8)

• A simulation calibrated limit on the HI power spectrum from the GMRT Epoch of Reionization experiment
• Science with the Murchison Widefield Array
• Foreground simulations for the LOFAR - Epoch of Reionization Experiment
• Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
• Fast Holographic Deconvolution: a new technique for precision radio interferometry
• Will point sources spoil 21 cm tomography?
• De-contamination of cosmological 21-cm maps
• New 145-MHz Source Measurements by PAPER in the Southern Sky

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• Prospects for detecting the 326.5 MHz redshifted 21 cm HI signal with the Ooty Radio Telescope (ORT)
• A Flux Scale for Southern Hemisphere 21cm EoR Experiments
• The giant lobes of Centaurus A observed at 118 MHz with the Murchison Widefield Array
• Beamforming Errors in Murchison Widefield Array Phased Array Antennas and their effects on Epoch of Reionization Science
• Sensitivity of the Hydrogen Epoch of Reionization Array and its Build-out Stages to One-point Statistics from Redshifted 21 cm Observations
• Calibration requirement for Epoch of Reionization 21-cm signal observation -- III. Bias and variance in uGMRT ELAIS-N1 field power spectrum
• It's Always Darkest Before the Cosmic Dawn: Early Results from Novel Tools and Telescopes for 21 cm Cosmology