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| Paper: |
Solving for Polarization Leakage in Radio Interferometers Using Unpolarized Source |
| Volume: |
295, Astronomical Data Analysis Software and Systems XII |
| Page: |
469 |
| Authors: |
Bhatnagar, S.; Urvashi, R. V.; Nityananda, R. |
| Abstract: |
This paper presents an algorithm for solving antenna based polarization leakage in a radio interferometer using co-polar observations of unpolarized sources. If ignored, polarization leakage manifests itself as closure errors in parallel hand (co-polar) visibilities. Many working radio telescopes offer observational advantages for observations in non-polar mode (e.g., higher frequency resolution, lower integration time, etc.). Many observations are therefore done in non-polar mode and the computation of antenna based leakage gains in co-polar visibilities is scientifically useful for debugging and calibrating the instrument. Also, this is a useful option to use when one cannot or does not want to put in the additional measurement effort to determine the leakage term by means of cross-polar measurements. We also present results from test data taken with the Giant Meterwave Radio Telescope (GMRT) and discuss the degeneracy in the solutions and the equivalence of the leakage induced closure phase and the Pancharatnam phase of optics. |
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