The Sun is a dynamic radio source, emitting across a wide range of intensities and polarization states — from the quiet Sun and faint coronal mass ejections (CMEs) to intense solar radio bursts. Traditionally, most solar radio studies have relied on dynamic spectra, which cannot provide information about source morphology, multiplicity, and spatial evolution. To fully understand the spatial and temporal complexity of these emissions, spectroscopic snapshot imaging is essential.
Over the past decade, new-generation radio interferometers such as the Murchison Widefield Array (MWA) and the Low Frequency Array (LOFAR) along with the recent advances in full-polarization calibration and imaging techniques have made it feasible to conduct such imaging studies with high fidelity. We have developed fully automated calibration and imaging pipelines — SImPL for the LOFAR and AIRCARS and P-AIRCARS for the MWA — that enable spectro-polarimetric snapshot imaging of the Sun. However, since these instruments are not dedicated solar observatories and offer limited observing time, we require robust, real-time triggering systems to capture transient solar events effectively.
In this talk, I will present the development and implementation of automated solar observation and imaging pipelines designed to address this need. I will focus on the real-time triggering mechanism developed for MWA and the recent advances in the LOFAR imaging pipeline, which now delivers images with 1–2 orders of magnitude improvement in dynamic range and fidelity. While the full-Stokes (polarization) capability is still under development for LOFAR, the progress thus far is very promising.
These technological and algorithmic developments are opening up new avenues in solar physics. I will conclude by presenting one such recent and intriguing discovery : the detection of linearly polarized emission from metric solar radio bursts. This result is surprising, as strong Faraday rotation in the solar corona is expected to depolarize any linear polarization generated at the source. I will discuss the evidence supporting this detection and its potential implications for our understanding of coronal plasma conditions and propagation effects.
Zoom link : https://cnrs.zoom.us/j/95003883304?pwd=MI0B5WLYiGZlzo3oAZUl5TAu4fta6q.1
