Coffee talks
Friday 26/06/2026 @ 11:30, Sala riunioni quarto piano e on-line (meet.google.com/sue-bwvk-axf)
Janhavi Baghel (University of Pretoria, South Africa), "Polarimetry at Low Radio Frequencies"
Low-frequency radio polarization provides an effective probe into the magnetic fields and magneto-ionic environments of astronomical sources. Magnetic fields play a fundamental role in a wide range of astrophysical processes, from star-forming regions and active galactic nuclei (AGN) jets to the large-scale structure of the Universe. These polarization measurements are particularly sensitive to Faraday rotation and depolarization, enabling characterization of the magnetic field structure and thermal electron content in and around cosmic objects. However, low-frequency polarimetry is especially challenging due to strong ionospheric effects, a scarcity of linearly polarized calibrators, higher instrumental polarization, more radio frequency interference, and more complex calibration techniques. Advances in sensitive radio interferometers such as the uGMRT, MeerKAT, and LOFAR have enabled detailed studies of polarized emission across a wide range of scales but have also brought along these challenges. In this talk, I will introduce the principles of low-frequency radio polarimetry, discuss the observational and calibration challenges unique to these frequencies, and highlight recent radio-polarimetric scientific results, particularly on AGN. I will conclude with future prospects for radio polarization studies using next-generation instruments such as the Square Kilometre Array.