TY  - JOUR
A1  - Martinez Gonzalez, M. J.
A1  - Pastor Yabar, A.
A1  - Lagg, A.
A1  - Asensio Ramos, A.
A1  - Collados Vera, M.
A1  - Solanki, S. K.
A1  - Balthasar, H.
A1  - Berkefeld, T.
A1  - Denker, Carsten
A1  - Doerr, H. P.
A1  - Feller, A.
A1  - Franz, M.
A1  - González Manrique, Sergio Javier
A1  - Hofmann, A.
A1  - Kneer, F.
A1  - Kuckein, Christoph
A1  - Louis, R.
A1  - von der Lühe, O.
A1  - Nicklas, H.
A1  - Orozco, D.
A1  - Rezaei, R.
A1  - Schlichenmaier, R.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Sigwarth, M.
A1  - Sobotka, M.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Verma, Meetu
A1  - Waldman, T.
A1  - Volkmer, R.
T1  - Inference of magnetic fields in the very quiet Sun
JF  - Journal of geophysical research : Earth surface
N2  - Context. Over the past 20 yr, the quietest areas of the solar surface have revealed a weak but extremely dynamic magnetism occurring at small scales (<500 km), which may provide an important contribution to the dynamics and energetics of the outer layers of the atmosphere. Understanding this magnetism requires the inference of physical quantities from high-sensitivity spectro-polarimetric data with high spatio-temporal resolution. Aims. We present high-precision spectro-polarimetric data with high spatial resolution (0.4") of the very quiet Sun at 1.56 mu m obtained with the GREGOR telescope to shed some light on this complex magnetism. Methods. We used inversion techniques in two main approaches. First, we assumed that the observed profiles can be reproduced with a constant magnetic field atmosphere embedded in a field-free medium. Second, we assumed that the resolution element has a substructure with either two constant magnetic atmospheres or a single magnetic atmosphere with gradients of the physical quantities along the optical depth, both coexisting with a global stray-light component. Results. Half of our observed quiet-Sun region is better explained by magnetic substructure within the resolution element. However, we cannot distinguish whether this substructure comes from gradients of the physical parameters along the line of sight or from horizontal gradients (across the surface). In these pixels, a model with two magnetic components is preferred, and we find two distinct magnetic field populations. The population with the larger filling factor has very weak (similar to 150 G) horizontal fields similar to those obtained in previous works. We demonstrate that the field vector of this population is not constrained by the observations, given the spatial resolution and polarimetric accuracy of our data. The topology of the other component with the smaller filling factor is constrained by the observations for field strengths above 250 G: we infer hG fields with inclinations and azimuth values compatible with an isotropic distribution. The filling factors are typically below 30%. We also find that the flux of the two polarities is not balanced. From the other half of the observed quiet-Sun area similar to 50% are two-lobed Stokes V profiles, meaning that 23% of the field of view can be adequately explained with a single constant magnetic field embedded in a non-magnetic atmosphere. The magnetic field vector and filling factor are reliable inferred in only 50% based on the regular profiles. Therefore, 12% of the field of view harbour hG fields with filling factors typically below 30%. At our present spatial resolution, 70% of the pixels apparently are non-magnetised.
KW  - Sun: atmosphere
KW  - Sun: magnetic fields
KW  - techniques: polarimetric
KW  - methods: observational
Y1  - 2016
U6  - https://doi.org/10.1051/0004-6361/201628449
SN  - 1432-0746
VL  - 596
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Verma, Meetu
A1  - Denker, Carsten
A1  - Balthasar, H.
A1  - Kuckein, Christoph
A1  - González Manrique, Sergio Javier
A1  - Sobotka, M.
A1  - Gonzalez, N. Bello
A1  - Hoch, S.
A1  - Diercke, Andrea
A1  - Kummerow, Philipp
A1  - Berkefeld, T.
A1  - Collados Vera, M.
A1  - Feller, A.
A1  - Hofmann, A.
A1  - Kneer, F.
A1  - Lagg, A.
A1  - Löhner-Böttcher, J.
A1  - Nicklas, H.
A1  - Pastor Yabar, A.
A1  - Schlichenmaier, R.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Schubert, M.
A1  - Sigwarth, M.
A1  - Solanki, S. K.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Volkmer, R.
A1  - von der Lühe, O.
A1  - Waldmann, T.
T1  - Horizontal flow fields in and around a small active region The transition period between flux emergence and decay
JF  - Polymers
N2  - Context. The solar magnetic field is responsible for all aspects of solar activity. Thus, emergence of magnetic flux at the surface is the first manifestation of the ensuing solar activity. Aims. Combining high-resolution and synoptic observations aims to provide a comprehensive description of flux emergence at photospheric level and of the growth process that eventually leads to a mature active region. Methods. The small active region NOAA 12118 emerged on 2014 July 17 and was observed one day later with the 1.5-m GREGOR solar telescope on 2014 July 18. High-resolution time-series of blue continuum and G-band images acquired in the blue imaging channel (BIC) of the GREGOR Fabry-Perot Interferometer (GFPI) were complemented by synoptic line-of-sight magnetograms and continuum images obtained with the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). Horizontal proper motions and horizontal plasma velocities were computed with local correlation tracking (LCT) and the differential affine velocity estimator (DAVE), respectively. Morphological image processing was employed to measure the photometric and magnetic area, magnetic flux, and the separation profile of the emerging flux region during its evolution. Results. The computed growth rates for photometric area, magnetic area, and magnetic flux are about twice as high as the respective decay rates. The space-time diagram using HMI magnetograms of five days provides a comprehensive view of growth and decay. It traces a leaf-like structure, which is determined by the initial separation of the two polarities, a rapid expansion phase, a time when the spread stalls, and a period when the region slowly shrinks again. The separation rate of 0.26 km s(-1) is highest in the initial stage, and it decreases when the separation comes to a halt. Horizontal plasma velocities computed at four evolutionary stages indicate a changing pattern of inflows. In LCT maps we find persistent flow patterns such as outward motions in the outer part of the two major pores, a diverging feature near the trailing pore marking the site of upwelling plasma and flux emergence, and low velocities in the interior of dark pores. We detected many elongated rapidly expanding granules between the two major polarities, with dimensions twice as large as the normal granules.
KW  - Sun: photosphere
KW  - Sun: magnetic fields
KW  - techniques: image processing
KW  - methods: data analysis
Y1  - 2016
U6  - https://doi.org/10.1051/0004-6361/201628380
SN  - 1432-0746
VL  - 596
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Balthasar, H.
A1  - Gömöry, P.
A1  - González Manrique, Sergio Javier
A1  - Kuckein, Christoph
A1  - Kavka, J.
A1  - Kucera, A.
A1  - Schwartz, P.
A1  - Vaskova, R.
A1  - Berkefeld, T.
A1  - Collados Vera, M.
A1  - Denker, Carsten
A1  - Feller, A.
A1  - Hofmann, A.
A1  - Lagg, A.
A1  - Nicklas, H.
A1  - Suarez, D.
A1  - Pastor Yabar, A.
A1  - Rezaei, R.
A1  - Schlichenmaier, R.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Sigwarth, M.
A1  - Sobotka, M.
A1  - Solanki, S. K.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Volkmer, R.
A1  - von der Lühe, O.
A1  - Waldmann, T.
T1  - Spectropolarimetric observations of an arch filament system with the GREGOR solar telescope
JF  - Astronomische Nachrichten = Astronomical notes
N2  - Arch filament systems occur in active sunspot groups, where a fibril structure connects areas of opposite magnetic polarity, in contrast to active region filaments that follow the polarity inversion line. We used the GREGOR Infrared Spectrograph (GRIS) to obtain the full Stokes vector in the spectral lines SiI lambda 1082.7 nm, He I lambda 1083.0 nm, and Ca I lambda 1083.9 nm. We focus on the near-infrared calcium line to investigate the photospheric magnetic field and velocities, and use the line core intensities and velocities of the helium line to study the chromospheric plasma. The individual fibrils of the arch filament system connect the sunspot with patches of magnetic polarity opposite to that of the spot. These patches do not necessarily coincide with pores, where the magnetic field is strongest. Instead, areas are preferred not far from the polarity inversion line. These areas exhibit photospheric downflows of moderate velocity, but significantly higher downflows of up to 30 km s(-1) in the chromospheric helium line. Our findings can be explained with new emerging flux where the matter flows downward along the field lines of rising flux tubes, in agreement with earlier results. (C) 2016 WILEY-VCH Verlag GmbH& Co. KGaA, Weinheim
KW  - Sun: filaments
KW  - Sun: photosphere
KW  - techniques: polarimetric
KW  - techniques: spectroscopic
Y1  - 2016
U6  - https://doi.org/10.1002/asna.201612432
SN  - 0004-6337
SN  - 1521-3994
VL  - 337
SP  - 1050
EP  - 1056
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Gonzalez Manrique, Sergio Javier
A1  - Kuckein, Christoph
A1  - Pastor Yabar, A.
A1  - Collados Vera, M.
A1  - Denker, Carsten
A1  - Fischer, C. E.
A1  - Gömöry, P.
A1  - Diercke, Andrea
A1  - Gonzalez, N. Bello
A1  - Schlichenmaier, R.
A1  - Balthasar, H.
A1  - Berkefeld, T.
A1  - Feller, A.
A1  - Hoch, S.
A1  - Hofmann, A.
A1  - Kneer, F.
A1  - Lagg, A.
A1  - Nicklas, H.
A1  - Orozco Suarez, D.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Sigwarth, M.
A1  - Sobotka, M.
A1  - Solanki, S. K.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Verma, Meetu
A1  - Volkmer, R.
A1  - von der Lühe, O.
A1  - Waldmann, T.
T1  - Fitting peculiar spectral profiles in He I 10830 angstrom absorption features
JF  - Astronomische Nachrichten = Astronomical notes
N2  - The new generation of solar instruments provides better spectral, spatial, and temporal resolution for a better understanding of the physical processes that take place on the Sun. Multiple-component profiles are more commonly observed with these instruments. Particularly, the He i 10830 triplet presents such peculiar spectral profiles, which give information on the velocity and magnetic fine structure of the upper chromosphere. The purpose of this investigation is to describe a technique to efficiently fit the two blended components of the He i 10830 triplet, which are commonly observed when two atmospheric components are located within the same resolution element. The observations used in this study were taken on 2015 April 17 with the very fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS) attached to the 1.5-m GREGOR solar telescope, located at the Observatorio del Teide, Tenerife, Spain. We apply a double-Lorentzian fitting technique using Levenberg-Marquardt least-squares minimization. This technique is very simple and much faster than inversion codes. Line-of-sight Doppler velocities can be inferred for a whole map of pixels within just a few minutes. Our results show sub-and supersonic downflow velocities of up to 32 km s(-1) for the fast component in the vicinity of footpoints of filamentary structures. The slow component presents velocities close to rest. (C) 2016 WILEY-VCH Verlag GmbH& Co. KGaA, Weinheim
KW  - Sun: chromosphere
KW  - methods: data analysis
KW  - techniques: spectroscopic
KW  - line: profiles
Y1  - 2016
U6  - https://doi.org/10.1002/asna.201512433
SN  - 0004-6337
SN  - 1521-3994
VL  - 337
SP  - 1057
EP  - 1063
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Verma, Meetu
A1  - Denker, Carsten
A1  - Böhm, F.
A1  - Balthasar, H.
A1  - Fischer, C. E.
A1  - Kuckein, Christoph
A1  - Gonzalez, N. Bello
A1  - Berkefeld, T.
A1  - Collados Vera, M.
A1  - Diercke, Andrea
A1  - Feller, A.
A1  - Gonzalez Manrique, Sergio Javier
A1  - Hofmann, A.
A1  - Lagg, A.
A1  - Nicklas, H.
A1  - Orozco Suarez, D.
A1  - Pator Yabar, A.
A1  - Rezaei, R.
A1  - Schlichenmaier, R.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Sigwarth, M.
A1  - Sobotka, M.
A1  - Solanki, S. K.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Volkmer, R.
A1  - von der Lühe, O.
A1  - Waldmann, T.
T1  - Flow and magnetic field properties in the trailing sunspots of active region NOAA 12396
JF  - Astronomische Nachrichten = Astronomical notes
N2  - Improved measurements of the photospheric and chromospheric three-dimensional magnetic and flow fields are crucial for a precise determination of the origin and evolution of active regions. We present an illustrative sample of multi-instrument data acquired during a two-week coordinated observing campaign in August 2015 involving, among others, the GREGOR solar telescope (imaging and near-infrared spectroscopy) and the space missions Solar Dynamics Observatory (SDO) and Interface Region Imaging Spectrograph (IRIS). The observations focused on the trailing part of active region NOAA 12396 with complex polarity inversion lines and strong intrusions of opposite polarity flux. The GREGOR Infrared Spectrograph (GRIS) provided Stokes IQUV spectral profiles in the photospheric Si i.1082.7 nm line, the chromospheric He I lambda 1083.0 nm triplet, and the photospheric Ca I lambda 1083.9 nm line. Carefully calibrated GRIS scans of the active region provided maps of Doppler velocity and magnetic field at different atmospheric heights. We compare quick-look maps with those obtained with the " Stokes Inversions based on Response functions" (SIR) code, which furnishes deeper insight into the magnetic properties of the region. We find supporting evidence that newly emerging flux and intruding opposite polarity flux are hampering the formation of penumbrae, i.e., a penumbra fully surrounding a sunspot is only expected after cessation of flux emergence in proximity to the sunspots. (C) 2016 WILEY-VCH Verlag GmbH& Co.KGaA, Weinheim
KW  - Sun: magnetic fields
KW  - sunspots
KW  - methods: data analysis
KW  - techniques: polarimetric
KW  - techniques: spectroscopic
Y1  - 2016
U6  - https://doi.org/10.1002/asna.201612447
SN  - 0004-6337
SN  - 1521-3994
VL  - 337
SP  - 1090
EP  - 1098
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Denker, Carsten
A1  - Heibel, C.
A1  - Rendtel, J.
A1  - Arlt, K.
A1  - Balthasar, H.
A1  - Diercke, Andrea
A1  - Gonzalez Manrique, Sergio Javier
A1  - Hofmann, A.
A1  - Kuckein, Christoph
A1  - Önel, H.
A1  - Valliappan, Senthamizh Pavai
A1  - Staude, J.
A1  - Verma, Meetu
T1  - Solar physics at the Einstein Tower
JF  - Astronomische Nachrichten = Astronomical notes
KW  - history and philosophy of astronomy
KW  - Sun: photosphere
KW  - Sun: magnetic fields
KW  - techniques: spectroscopic
KW  - telescopes
Y1  - 2016
U6  - https://doi.org/10.1002/asna.201612442
SN  - 0004-6337
SN  - 1521-3994
VL  - 337
SP  - 1105
EP  - 1113
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kuckein, Christoph
A1  - Diercke, Andrea
A1  - González Manrique, Sergio Javier
A1  - Verma, Meetu
A1  - Loehner-Boettcher, Johannes
A1  - Socas-Navarro, H.
A1  - Balthasar, Horst
A1  - Sobotka, M.
A1  - Denker, Carsten
T1  - Ca II 8542 angstrom brightenings induced by a solar microflare
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. We study small-scale brightenings in Ca II 8542 angstrom line-core images to determine their nature and effect on localized heating and mass transfer in active regions. Methods. High-resolution two-dimensional spectroscopic observations of a solar active region in the near-infrared Ca II 8542 angstrom line were acquired with the GREGOR Fabry-Perot Interferometer attached to the 1.5-m GREGOR telescope. Inversions of the spectra were carried out using the NICOLE code to infer temperatures and line-of-sight (LOS) velocities. Response functions of the Ca II line were computed for temperature and LOS velocity variations. Filtergrams of the Atmospheric Imaging Assembly (AIA) and magnetograms of the Helioseismic and Magnetic Imager (HMI) were coaligned to match the ground-based observations and to follow the Ca II brightenings along all available layers of the atmosphere. Results. We identified three brightenings of sizes up to 2 ' x 2 ' that appeared in the Ca II 8542 angstrom line-core images. Their lifetimes were at least 1.5 min. We found evidence that the brightenings belonged to the footpoints of a microflare (MF). The properties of the observed brightenings disqualified the scenarios of Ellerman bombs or Interface Region Imaging Spectrograph (IRIS) bombs. However, this MF shared some common properties with flaring active-region fibrils or flaring arch filaments (FAFs): (1) FAFs and MFs are both apparent in chromospheric and coronal layers according to the AIA channels; and (2) both show flaring arches with lifetimes of about 3.0-3.5 min and lengths of similar to 20 ' next to the brightenings. The inversions revealed heating by 600 K at the footpoint location in the ambient chromosphere during the impulsive phase. Connecting the footpoints, a dark filamentary structure appeared in the Ca II line-core images. Before the start of the MF, the spectra of this structure already indicated average blueshifts, meaning upward motions of the plasma along the LOS. During the impulsive phase, these velocities increased up to -2.2 km s(-1). The structure did not disappear during the observations. Downflows dominated at the footpoints. However, in the upper photosphere, slight upflows occurred during the impulsive phase. Hence, bidirectional flows are present in the footpoints of the MF.
KW  - Sun: photosphere
KW  - Sun: chromosphere
KW  - Sun: corona
KW  - Sun: activity
KW  - techniques: imaging spectroscopy
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201731319
SN  - 1432-0746
VL  - 608
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Gömöry, Peter
A1  - Balthasar, Horst
A1  - Kuckein, Christoph
A1  - Koza, Julis
A1  - Veronig, Astrid M.
A1  - González Manrique, Sergio Javier
A1  - Kucera, Ales
A1  - Schwartz, Pavol
A1  - Hanslmeier, Arnold
T1  - Flare-induced changes of the photospheric magnetic field in a delta-spot deduced from ground-based observations
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. Changes of the magnetic field and the line-of-sight velocities in the photosphere are being reported for an M-class flare that originated at a delta-spot belonging to active region NOAA 11865. Methods. High-resolution ground-based near-infrared spectropolarimetric observations were acquired simultaneously in two photospheric spectral lines, Fe I 10783 angstrom and Si I 10786 angstrom, with the Tenerife Infrared Polarimeter at the Vacuum Tower Telescope (VTT) in Tenerife on 2013 October 15. The observations covered several stages of the M-class flare. Inversions of the full-Stokes vector of both lines were carried out and the results were put into context using (extreme)-ultraviolet filtergrams from the Solar Dynamics Observatory (SDO). Results. The active region showed high flaring activity during the whole observing period. After the M-class flare, the longitudinal magnetic field did not show significant changes along the polarity inversion line (PIL). However, an enhancement of the transverse magnetic field of approximately 550G was found that bridges the PIL and connects umbrae of opposite polarities in the delta-spot. At the same time, a newly formed system of loops appeared co-spatially in the corona as seen in 171 angstrom filtergrams of the Atmospheric Imaging Assembly (AIA) on board SDO. However, we cannot exclude that the magnetic connection between the umbrae already existed in the upper atmosphere before the M-class flare and became visible only later when it was filled with hot plasma. The photospheric Doppler velocities show a persistent upflow pattern along the PIL without significant changes due to the flare. Conclusions. The increase of the transverse component of the magnetic field after the flare together with the newly formed loop system in the corona support recent predictions of flare models and flare observations.
KW  - Sun: magnetic fields
KW  - sunspots
KW  - Sun: photosphere
KW  - Sun: flares
KW  - techniques: polarimetric
Y1  - 2017
U6  - https://doi.org/10.1051/0004-6361/201730644
SN  - 1432-0746
VL  - 602
SP  - 14
EP  - 27
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Gonzalez Manrique, Sergio Javier
A1  - Kuckein, Christoph
A1  - Collados, M.
A1  - Denker, Carsten
A1  - Solanki, S. K.
A1  - Gomory, P.
A1  - Verma, Meetu
A1  - Balthasar, H.
A1  - Lagg, A.
A1  - Diercke, Andrea
T1  - Temporal evolution of arch filaments as seen in He I 10 830 angstrom
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. We study the evolution of an arch filament system (AFS) and of its individual arch filaments to learn about the processes occurring in them. Methods. We observed the AFS at the GREGOR solar telescope on Tenerife at high cadence with the very fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS) in the He I 10 830 angstrom spectral range. The He I triplet profiles were fitted with analytic functions to infer line-of-sight (LOS) velocities to follow plasma motions within the AFS. Results. We tracked the temporal evolution of an individual arch filament over its entire lifetime, as seen in the He I 10 830 angstrom triplet. The arch filament expanded in height and extended in length from 13 ' to 21 '. The lifetime of this arch filament is about 30 min. About 11 min after the arch filament is seen in He I, the loop top starts to rise with an average Doppler velocity of 6 km s(-1). Only two minutes later, plasma drains down with supersonic velocities towards the footpoints reaching a peak velocity of up to 40 km s(-1) in the chromosphere. The temporal evolution of He I 10 830 angstrom profiles near the leading pore showed almost ubiquitous dual red components of the He I triplet, indicating strong downflows, along with material nearly at rest within the same resolution element during the whole observing time.
KW  - Sun: chromosphere
KW  - Sun: activity
KW  - methods: observational
KW  - methods: data analysis
KW  - techniques: high angular resolution
Y1  - 2018
U6  - https://doi.org/10.1051/0004-6361/201832684
SN  - 1432-0746
VL  - 617
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Denker, Carsten
A1  - Kuckein, Christoph
A1  - Verma, Meetu
A1  - Manrique Gonzalez, Sergio Javier Gonzalez
A1  - Diercke, Andrea
A1  - Enke, Harry
A1  - Klar, Jochen
A1  - Balthasar, Horst
A1  - Louis, Rohan E.
A1  - Dineva, Ekaterina
T1  - High-cadence Imaging and Imaging Spectroscopy at the GREGOR Solar Telescope-A Collaborative Research Environment for High-resolution Solar Physics
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series
N2  - In high-resolution solar physics, the volume and complexity of photometric, spectroscopic, and polarimetric ground-based data significantly increased in the last decade, reaching data acquisition rates of terabytes per hour. This is driven by the desire to capture fast processes on the Sun and the necessity for short exposure times "freezing" the atmospheric seeing, thus enabling ex post facto image restoration. Consequently, large-format and high-cadence detectors are nowadays used in solar observations to facilitate image restoration. Based on our experience during the "early science" phase with the 1.5 m GREGOR solar telescope (2014–2015) and the subsequent transition to routine observations in 2016, we describe data collection and data management tailored toward image restoration and imaging spectroscopy. We outline our approaches regarding data processing, analysis, and archiving for two of GREGOR's post-focus instruments (see http://gregor.aip.de), i.e., the GREGOR Fabry–Pérot Interferometer (GFPI) and the newly installed High-Resolution Fast Imager (HiFI). The heterogeneous and complex nature of multidimensional data arising from high-resolution solar observations provides an intriguing but also a challenging example for "big data" in astronomy. The big data challenge has two aspects: (1) establishing a workflow for publishing the data for the whole community and beyond and (2) creating a collaborative research environment (CRE), where computationally intense data and postprocessing tools are colocated and collaborative work is enabled for scientists of multiple institutes. This requires either collaboration with a data center or frameworks and databases capable of dealing with huge data sets based on virtual observatory (VO) and other community standards and procedures.
KW  - astronomical databases
KW  - methods: data analysis
KW  - Sun: chromosphere
KW  - Sun: photosphere
KW  - techniques: image processing
KW  - techniques: spectroscopic
Y1  - 2018
U6  - https://doi.org/10.3847/1538-4365/aab773
SN  - 0067-0049
SN  - 1538-4365
VL  - 236
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -