Volume 596, December 2016
GREGOR first results
|Number of page(s)||6|
|Published online||30 November 2016|
Slipping reconnection in a solar flare observed in high resolution with the GREGOR solar telescope⋆
1 Astronomical Institute, Academy of Sciences of the Czech Republic, Fričova 298, 251 65 Ondřejov, Czech Republic
2 Leibniz Institute for Astrophysics Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
3 Kiepenheuer Institute for Solar Physics, Schöneckstraße 6, 79104 Freiburg, Germany
4 Instituto de Astrofísica de Canarias, vía Láctea, 38200 La Laguna, Tenerife, Spain
5 Max-Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
6 Institute of Astrophysics, Georg-August University Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
7 National Solar Observatory, 3010 Coronal Loop, Sunspot, NM 88349, USA
8 School of Space Research, Kyung Hee University, Yongin, 446-701 Gyeonggi-Do, Korea
Received: 15 December 2015
Accepted: 15 April 2016
A small flare ribbon above a sunspot umbra in active region 12205 was observed on November 7, 2014, at 12:00 UT in the blue imaging channel of the 1.5 m GREGOR telescope, using a 1 Å Ca ii H interference filter. Context observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO), the Solar Optical Telescope (SOT) onboard Hinode, and the Interface Region Imaging Spectrograph (IRIS) show that this ribbon is part of a larger one that extends through the neighboring positive polarities and also participates in several other flares within the active region. We reconstructed a time series of 140 s of Ca ii H images by means of the multiframe blind deconvolution method, which resulted in spatial and temporal resolutions of 0.1″ and 1 s. Light curves and horizontal velocities of small-scale bright knots in the observed flare ribbon were measured. Some knots are stationary, but three move along the ribbon with speeds of 7–11 km s-1. Two of them move in the opposite direction and exhibit highly correlated intensity changes, which provides evidence of a slipping reconnection at small spatial scales.
Key words: Sun: flares / Sun: chromosphere
Movies associated to Figs. 1 and 2 are available at http://www.aanda.org
© ESO, 2016
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