New Limits on Polarized Power Spectra at 126 and 164 MHz: Relevance to Epoch of Reionization Measurements

Abstract

Polarized foreground emission is a potential contaminant of attempts to measure the fluctuation power spectrum of highly redshifted 21 cm HI emission from the epoch of reionization. Using the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER), we present limits on the observed power spectra of all four Stokes parameters in two frequency bands, centered at 126 MHz ($z=10.3$) and 164 MHz ($z=7.66$) for a three-month observing campaign of a 32-antenna deployment, for which unpolarized power spectrum results have been reported at $z=7.7$ (Parsons et al 2014) and $7.5<z<10.5$ (Jacobs et al 2014). The power spectra in this paper are processed in the same way as in those works, and show no definitive detection of polarized power. This non-detection appears to be largely due to the suppression of polarized power by ionospheric rotation measure fluctuations, which strongly affect Stokes Q and U. We are able to show that the net effect of polarized leakage is a negligible contribution at the levels of of the limits reported in Parsons et al 2014 and Jacobs et al 2014.

Accepted by ApJ

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• A simplified, lossless re-analysis of PAPER-64
• The Impact of Modeling Errors on Interferometer Calibration for 21 cm Power Spectra
• First Limits on the 21 cm Power Spectrum during the Epoch of X-ray heating
• The challenges of low-frequency radio polarimetry: lessons from the Murchison Widefield Array
• Understanding the Diversity of 21 cm Cosmology Analyses
• Statistics of the epoch of reionization (EoR) 21-cm signal -- II. The evolution of the power spectrum error-covariance
• Measuring Phased-Array Antenna Beampatterns with High Dynamic Range for the Murchison Widefield Array using 137 MHz ORBCOMM Satellites
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• Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure
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• Simulations of Galactic polarized synchrotron emission for Epoch of Reionization observations
• The HERA-19 Commissioning Array: Direction Dependent Effects
• Ionospheric Attenuation of Polarized Foregrounds in 21 cm Epoch of Reionization Measurements: A Demonstration for the HERA Experiment
• Detecting primordial gravitational waves with circular polarization of the redshifted 21 cm line: I. Formalism
• Detecting primordial gravitational waves with circular polarization of the redshifted 21 cm line: II. Forecasts
• Strategy for mitigation of systematics for EoR experiments with the Murchison Widefield Array
• External Calibrator in Global Signal Experiment for Detection of the Epoch of Reionization