Stokes imaging polarimetry using image restoration at the Swedish 1-m solar telescope

• Published in: Astronomy and astrophysics (Berlin) 2008-10, Vol.489 (1), p.429-440
• Main Authors: van Noort, M. J., Rouppe van der Voort, L. H. M.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; methods: observational; plages; Sun: faculae; Sun: magnetic fields; sunspots; techniques: image processing; techniques: polarimetric
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:200809959

Aims. We aim to achieve both high spatial resolution and high polarimetric sensitivity, using an earth-based 1m-class solar telescope, for the study of magnetic fine structure on the surface of the Sun. Methods. We use a setup with 3 high-speed, low-noise cameras to construct datasets with interleaved polarimetric states, particularly suitable for Multi-Object Multi-Frame Blind Deconvolution image restorations. We discuss the polarimetric calibration routine and various potential sources of error in the results. Results. We obtained near diffraction limited images, which have a noise level of $\approx 10^{-3} I_{\rm cont}$. We confirm that dark cores have a weaker magnetic field and a lower inclination angle with respect to the solar surface than the edges of the penumbral filament. We demonstrate that the magnetic field strength in faculae-striations is significantly lower than in other nearby parts of the faculae.