Articles written in Journal of Astrophysics and Astronomy
Volume 44 All articles Published: 16 January 2023 Article ID 0002 ORIGINAL RESULTS
Exploring Earth’s ionosphere and its effect on low radio frequency observation with the uGMRT and the SKA
SARVESH MANGLA SUMANJIT CHAKRABORTY ABHIRUP DATTA ASHIK PAUL
The Earth’s ionosphere introduces systematic effects that limit the performance of a radio interferometer at low frequencies ($\lesssim$1 GHz). These effects become more pronounced for severe geomagnetic activities or observations involving longer interferometer baselines. The uGMRT, a pathfinder for the Square Kilometre Array (SKA), is located between the northern crest of the Equatorial ionisation Anomaly (EIA) and the magnetic equator. Hence, this telescope is more prone to severe ionospheric conditions and is a unique radio interferometer for studying the ionosphere. Here, we present 235MHz observations with the GMRT, showingsignificant ionospheric activities over a solar minimum. This work has characterised the ionospheric disturbances observed with the GMRT. We have compared them with ionospheric studies and observations with other telescopes like the VLA, MWA and LOFAR situated at different magnetic latitudes. We have estimated the ionospheric total electron content (TEC) gradient over the full GMRT array, showing an order of magnitude higher sensitivity than the Global Navigation Satellite System (GNSS). Furthermore, this article uses the ionospheric characteristics estimated from the observations with uGMRT, VLA, LOFAR and MWA to forecast the effects of the low-frequency observations with the SKA1-MID and SKA1-LOW in the future.
Volume 44, 2023
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