First high-resolution images of the Sun in the 2796 Å Mg II k line

Abstract

We present the first high-resolution solar images in the Mg II k 2796 Å line. The images, taken through a 4.8 Å broad interference filter, were obtained during the second science flight of SUNRISE in June 2013 by the SuFI instrument. The Mg II k images display structures that look qualitatively very similar to images taken in the core of Ca II H. The Mg II images exhibit reversed granulation (or shock waves) in the internetwork regions of the quiet Sun, at intensity contrasts that are similar to those found in Ca II H. Very prominent in Mg II are bright points, both in the quiet Sun and in plage regions, particularly near disk center. These are much brighter than at other wavelengths sampled at similar resolution. Furthermore, Mg II k images also show fibril structures associated with plage regions. Again, the fibrils are similar to those seen in Ca II H images, but tend to be more pronounced, particularly in weak plage.

Accepted for publication in The Astrophysical Journal Letters

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• A Tale of Two Emergences: Sunrise II Observations of Emergence Sites in a Solar Active Region
• Mg ii h&k spectra of an enhanced network region simulated with the MURaM-ChE code. Results using 1.5D synthesis
• On the inversion of the scattering polarization and the Hanle effect signals in the hydrogen Lyman-$\alpha$ line
• The Sunrise Chromospheric Infrared Spectro-Polarimeter SCIP: an instrument for SUNRISE III