Ongoing Theses

Sunspots play an important role in understanding the dynamical nature of the solar magnetic field. Although their surface appearance has been observed for over four centuries, little is known about the subsurface structure. Sunspots are known to strongly influence solar acoustic modes and there is a...

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With increasing aperture size of telescopes, the maximum possible theoretical resolution of observations increases as well. This leads to the possibility of observing structures and phenomena, which have not been discovered yet. With the help of the solar telescope GREGOR, these observations can be...

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Standard algorithms for tracking small scale magnetic features suffer
from ambiguities due to the intrinsic complexity of the feature
interactions which are driven by photospheric convective motions.

In his Ph.D. work, Andrei Gorobets will work on an alternative concept
for tracking the evolution...

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Theses

The topic of this thesis are the changes to spectral line profiles observed in varying heights of the solar atmosphere. Gas motions in the atmosphere manifest as Doppler shifts and asymmetries in the line profiles. These changes vary over the solar disk, depending on the conditions of the line...

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Formation of Intergranular Lanes and Acoustic Events

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The vertical component of the magnetic field B⊥ was determined and evaluated at the boundary between the penumbra and the umbra for 11 fully developed sunspots observed with the GRIS@GREGOR instrument.

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Context. Understanding the solar activity cycle - its origin, the mechanisms that drive it, and its relation to stellar activity cycles - is an outstanding open issue in solar and stellar astrophysics. Helio- and asteroseismology have developed into powerful tools to gain insight into the interior...

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Context. Jurcak et al. (submitted to A&A) found no dependence of the vertical magnetic field component <|Bver|>ψ at the umbral boundary of sunspots on area in their statistical study of 79 active regions, whereby <.>ψ stands for average along the contour.

Aims. We investigate the temporal...

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This doctoral dissertation is primarily focused on the study of the solar atmosphere, the outermost part

of our Star. The main goal of this work is to improve our understanding of the solar atmospheric structure using helioseismic methods. The research conducted for this thesis is based primarily...

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Understanding the solar meridional flow is important for uncovering the origin of the solar activity cycle. Yet, recent helioseismic estimates of this flow have come to conflicting conclusions in deeper layers of the solar interior, i.e., at depths below about 0.9 solar radii.

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For terrestrial climatology, the continuous measurement of the total (TSI) and spectral solar irradiance (SSI) between the EUV and IR spectral regions is of great importance.

Since 2008, the EUV region has been covered by the measurements of SolACES (Solar Auto Calibrating EUV Spectrometer)...

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The goal of this bachelor thesis is the study of magnetic properties of solar pores. The observation of the sunspots and pores in this thesis are done with the GREGOR telescope at the Observatorio del Teide in Teneriffe.

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Das Ziel der vorliegenden Bachelorarbeit bestand darin, die konvektive Blauverschiebung in der Photosphäre der Sonne zu untersuchen. Dazu wurde die Spektrallinie Fe I 617,333 52 nm spektroskopisch beobachtet und analysiert. Es sollte festgestellt werden, ob die Mitte-Rand-Variation dieser...

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