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Sparse inversion of Stokes profiles I. Two-dimensional Milne-Eddington inversions
Stockholm University, Faculty of Science, Department of Astronomy.
Number of Authors: 2
2015 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 577, A140Article in journal (Refereed) Published
Abstract [en]

Context. Inversion codes are numerical tools used to infer physical properties from observations. Despite their success, the quality of current spectropolarimetric observations and those expected in the near future presents a challenge to current inversion codes. Aims. The pixel-by-pixel strategy of inverting spectropolarimetric data that we currently use needs to be surpassed and improved. The inverted physical parameters have to take into account the spatial correlation that is present in the data and that contains valuable physical information. Methods. We used the concept of sparsity or compressibility to develop a new generation of inversion codes for the Stokes parameters. The inversion code uses numerical optimization techniques based on the idea of proximal algorithms to impose sparsity. In so doing, we allow for the first time exploiting the spatial correlation on the maps of physical parameters. Sparsity also regularizes the solution by reducing the number of unknowns. Results. We compare the results of the new inversion code with pixel-by-pixel inversions to demonstrate the increased robustness of the solution. We also show how the method can easily compensate for the effect of the telescope point spread function, producing solutions with an enhanced contrast.

Place, publisher, year, edition, pages
2015. Vol. 577, A140
Keyword [en]
Sun: magnetic fields, Sun: atmosphere, line: profiles, methods: data analysis
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:su:diva-119761DOI: 10.1051/0004-6361/201425508ISI: 000357345900092OAI: diva2:848827
Available from: 2015-08-26 Created: 2015-08-24 Last updated: 2015-08-26Bibliographically approved

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de la Cruz Rodriguez, Jaime
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