High-resolution 3D flow fields around solar active regions

Accurate measurements of magnetic and velocity fields in and around solar active regions are key to unlocking the mysteries of the formation and the decay of sunspots. High spatial resolution image and spectral sequences with a high cadence obtained with the GREGOR solar telescope give us an opportunity to scrutinize 3-D flow fields with local correlation tracking (LCT) and imaging spectroscopy. We present GREGOR early science data acquired in July/August 2014 with the GREGOR Fabry-Pérot Interferometer (GFPI) and the Blue Imaging Channel (BIC). Time-series of blue continuum images (λ 450.6 nm) images of the emerging flux region NOAA 12118 were restored with the speckle masking technique to derive horizontal proper motions and to track the evolution of morphological changes. Growth and decay rates for area and magnetic flux are presented. In addition, we searched the GREGOR/GFPI data archive for occasions when new flux emerges or old flux decays and present the respective Doppler maps. All high resolution observations are discussed in the context of synoptic data from the Solar Dynamics Observatory (SDO).

The 1.5-meter GREGOR solar telescope was built by a German consortium under the leadership of the Kiepenheuer Institute for Solar Physics in Freiburg with the Leibniz Institute for Astrophysics Potsdam, the Institute for Astrophysics Göttingen, and the Max Planck Institute for Solar System Research in Göttingen as partners, and with contributions by the Instituto de Astrofísica de Canarias, the Istituto Ricerche Solari Locarno, and the Astronomical Institute of the Academy of Sciences of the Czech Republic.