CYBERSKA

 A Cyberinfrastructure platform to meet the needs of data intensive radio astronomy on route to the SKA

Faraday synthesis: The synergy of aperture and rotation measure synthesis

http://arxiv.org/abs/1112.4175

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.

Comments

  • Samuel George 2547 days ago

    This looks very promising. I tried to get hold of their implementation "fsimager" but I don't see a link for it in the paper or on the author's homepages. This would be very interesting to implement for GALFACTS.

  • Kevin Douglas 2547 days ago

    Sam, pardon my ignorance (still learning this polarisation stuff) but how would this apply to single-dish observations?

  • Samuel George 2547 days ago

    Ah yes, pardon my stupid comment! :-) I had meant to say POSSUM when I wrote this earlier - but was thinking about GALFACTS (and checking something I'd stuck in the RM synthesis report that this jogged by memory on) and hence wrote the wrong acronym.