Correcting the polarization leakage phases and amplitudes throughout the primary beam of an interferometer

Authors

  • R. I. Reid,

    1. Dominion Radio Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Penticton, British Columbia, Canada
    2. Now at National Radio Astrophysical Observatory, Charlottesville, Virginia, USA.
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  • A. D. Gray,

    1. Dominion Radio Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Penticton, British Columbia, Canada
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  • T. L. Landecker,

    1. Dominion Radio Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Penticton, British Columbia, Canada
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  • A. G. Willis

    1. Dominion Radio Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, Penticton, British Columbia, Canada
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Abstract

[1] Polarimetric observations are affected by leakage of unpolarized light into the polarization channels, in a way that varies with the angular position of the source relative to the optical axis. The off-axis part of the leakage is often corrected by subtracting the product of the unpolarized map and a leakage map from each polarization image, but it is seldom realized that heterogeneities in the array shift the loci of the leaked radiation in a baseline-dependent fashion. We present here a method to measure and remove the wide-field polarization leakage of a heterogeneous array. The process also maps the complex voltage patterns of each antenna, which can be used to correct all Stokes parameters for imaging errors due to the primary beams.

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