Study Reveals Complex Faraday Rotation in Distant Radio Galaxy Using ASKAP Observations
Astronomers analyzed a distant radio galaxy using the Australian Square Kilometre Array Pathfinder (ASKAP) and discovered complex patterns of Faraday rotation—the twisting of polarized radio waves as they travel through magnetized regions. The source, RACS_0900-28_7036, showed unusually high rotation measures and evidence of multiple magnetized layers along the line of sight. This detailed characterization demonstrates how broadband radio observations can map turbulent magnetic environments in distant galaxies and improve our understanding of cosmic magnetism.
Researchers conducted a broadband spectro-polarimetric analysis of an extragalactic radio source using ASKAP observations spanning 803–1083 MHz across 36 spectral channels. The source was selected for its exceptionally large rotation measure (345.7 rad m⁻²) and strong evidence of Faraday complexity, indicating multiple magnetized regions affecting the polarized radio waves. Using Bayesian model selection, the team identified a multi-component structure comprising one dominant Faraday-active region and two secondary depolarization components, with the primary component showing a rotation measure of approximately 345.5 rad m⁻² and the secondary component at 131.5 rad m⁻² with stronger depolarization. The analysis of the fractional polarization spectrum and the evolution of polarization properties in the q–u plane confirmed the presence of multiple Faraday-active regions along the line of sight. These findings establish a framework for systematic depolarization studies across the SPICE-RACS catalog and enable statistical investigations of Faraday complexity in diverse extragalactic radio sources.
What different sources said
- arXiv astro-phCenter
Faraday Complexity and Depolarisation in a High-Rotation-Measure Radio Galaxy from the Spectra and Polarisation In Cutouts of Extragalactic Sources (SPICE-RACS) DR2
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