Faraday synthesis: The synergy of aperture and rotation measure synthesis

Abstract

We introduce a new technique for imaging the polarized radio sky using interferometric data. The new approach, which we call Faraday synthesis, combines aperture and rotation measure synthesis imaging and deconvolution into a single algorithm. This has several inherent advantages over the traditional two-step technique, including improved sky plane resolution, fidelity, and dynamic range. In addition, the direct visibility- to Faraday-space imaging approach is a more sound foundation on which to build more sophisticated deconvolution or inference algorithms. For testing purposes, we have implemented a basic Faraday synthesis imaging software package including a three-dimensional CLEAN deconvolution algorithm. We compare the results of this new technique to those of the traditional approach using mock data. We find many artifacts in the images made using the traditional approach that are not present in the Faraday synthesis results. In all, we achieve a higher spatial resolution, an improvement in dynamic range of about 20%, and a more accurate reconstruction of low signal to noise source fluxes when using the Faraday synthesis technique.

11 pages, 5 figures, submitted to A&A

References in corpus (8)

• Correcting direction-dependent gains in the deconvolution of radio interferometric images
• Antisymmetry in the Faraday Rotation Sky Caused by a Nearby Magnetized Bubble
• The application of compressive sampling to radio astronomy II: Faraday rotation measure synthesis
• Wide field polarimetry around the Perseus cluster at 350 MHz
• Sparse Faraday Rotation Measure Synthesis
• Reconstructing signals from noisy data with unknown signal and noise covariance
• GMIMS: The Global Magneto-Ionic Medium Survey
• Faraday caustics: Singularities in the Faraday spectrum and their utility as probes of magnetic field properties

Cited by in corpus (18)

• Calibrating High-Precision Faraday Rotation Measurements for LOFAR and the Next Generation of Low-Frequency Radio Telescopes
• Comparison of algorithms for determination of rotation measure and Faraday structure I. 1100 - 1400 MHz
• Recognizing magnetic structures by present and future radio telescopes with Faraday rotation measure synthesis
• Multi-frequency Black Hole Imaging for the Next-Generation Event Horizon Telescope
• Using rotation measure grids to detect cosmological magnetic fields -- a Bayesian approach
• RMTable2023 and PolSpectra2023: standards for reporting polarization and Faraday rotation measurements of radio sources
• Faraday signature of magnetic helicity from reduced depolarization
• A new approach to multi-frequency synthesis in radio interferometry
• Sparse interferometric Stokes imaging under polarization constraint (Polarized SARA)
• The LOFAR View of Cosmic Magnetism
• A Faraday Rotation Study of the Stellar Bubble and HII Region Associated with the W4 Complex
• Denser Sampling of the Rosette Nebula with Faraday Rotation Measurements: Improved Estimates of Magnetic Fields in HII Regions
• The Global Magneto-Ionic Medium Survey (GMIMS): The brightest polarized region in the Southern sky at 75cm and its implications for Radio Loop II
• Wide-band Rotation Measure Synthesis
• Improved CLEAN reconstructions for rotation measure synthesis with maximum likelihood estimation
• The Galactic Faraday rotation sky 2020
• Semi-Supervised Rotation Measure Deconvolution and its application to MeerKAT observations of galaxy clusters
• Direction-Dependent Faraday Synthesis