Abstract Details
| Name: Jais Kumar Affiliation: Department of Physics, IIT (BHU) Varanasi. Conference ID: ASI2018_1665 Title : Polarization calibration and its need in radio astronomy Authors and Co-Authors : Dr. Prasun Dutta; Department of Physics, IIT (BHU) Varanasi; Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : The four stokes parameters that can be inferred from the observed visibilities from an interferometer carry information related to the astrophysical sources. Post observation, first step is to understand and calibrate for the antenna gain and leakages. Most of the science objectives behind the observations require to estimate the stokes I parameter, that gives the total intensity. Generally for the strong sources the leakage from the other parameters into stokes I is very minimal and hence is neglected. However, for observations which requires very high dynamic range in stokes I, such assumptions may give rise to erroneous results. Moreover, if polarized intensity is to be measured, polarization calibration is a necessity and the effect of the leakage is also to be calibrated. In the standard polarization calibration processes we neglect any second order effect of leakage. Though this is apparently a good approximation, for observations like the Hi signal from the Epoch of Reionization (EoR) etc, where the signal visibilities with high amplitudes is comparable to the smaller amplitude visibilities, one need to investigate the applicability of the standard algorithm. In this work we have investigated the limitations of the standard algorithms for the polarization calibration for an interferometer and explored the feasibility of application of higher order polarization calibration algorithms to calibrate the observed visibilities. |