Journal Article

<span class="smallCaps">music</span> for Faraday rotation measure synthesis

M. Andrecut

in Monthly Notices of the Royal Astronomical Society: Letters

Published on behalf of The Royal Astronomical Society

Volume 430, issue 1, pages L15-L19
Published in print March 2013 |
Published online December 2012 | e-ISSN: 1745-3933 | DOI: https://dx.doi.org/10.1093/mnrasl/sls040

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Faraday rotation measure (RM) synthesis requires the recovery of the Faraday dispersion function (FDF) from measurements restricted to limited wavelength ranges, which is an ill-conditioned deconvolution problem. Here, we propose a novel deconvolution method based on an extension of the MUltiple SIgnal Classification (music) algorithm. The complexity and speed of the method is determined by the eigen-decomposition of the covariance matrix of the observed polarizations. We show numerically that for high to moderate signal-to-noise ratio (S/N) cases the rm-music method is able to recover the Faraday depth values of closely spaced pairs of thin RM components, even in situations where the peak response of the FDF is outside of the RM range between the two input RM components. This result is particularly important because the standard deconvolution approach based on rm-clean fails systematically in such situations, due to its greedy mechanism used to extract the RM components. For low S/N situations, both the rm-music and rm-clean methods provide similar results.

Keywords: magnetic fields; methods: data analysis; techniques: polarimetric

Journal Article.  3100 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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