492 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- W. Schmidt2 profiles60 · h 35
- S. Berdyugina2 profiles44 · h 28
- J. C. del Toro Iniesta36 · h 22
- R. Schlichenmaier36 · h 29
- A. Gandorfer34 · h 32
- V. Pillet34 · h 38
- S. Solanki3 profiles32 · h 78
- J. Borrero31 · h 24
- C. Beck3 profiles30 · h 24
- O. Steiner3 profiles30 · h 20
- M. Knölker28 · h 25
- M. Roth2 profiles27 · h 69
- Instituto de Astrofísica de CanariasES144 papers
- Max Planck Institute for Solar System ResearchDE129 papers
- Universidad de La LagunaES103 papers
- Instituto de Astrofísica de AndalucíaES83 papers
- Centre National de la Recherche ScientifiqueFR68 papers
- Leibniz Institute for Astrophysics PotsdamDE62 papers
- Kyung Hee UniversityKR61 papers
- NSF NCAR High Altitude ObservatoryUS61 papers
- National Solar ObservatoryUS60 papers
- Istituto Ricerche Solari LocarnoCH56 papers
- Czech Academy of Sciences, Astronomical InstituteCZ54 papers
- University of GöttingenDE47 papers
79 papers · 1 filter
First measurement of the magnetic field on FK Com and its relation to the contemporaneous starspot locations
H. Korhonen, S. Hubrig, S. V. Berdyugina +5
In this study we present simultaneous low-resolution longitudinal magnetic field measurements and high-resolution spectroscopic observations of the cool single giant FK Com. The va…
Sunspots: from small-scale inhomogeneities towards a global theory
Rolf Schlichenmaier
The penumbra of a sunspot is a fascinating phenomenon featuring complex velocity and magnetic fields. It challenges both our understanding of radiative magneto-convection and our m…
Optical configuration and analysis of the AMBER/VLTI instrument
S. Robbe-Dubois, S. Lagarde, R. G. Petrov +23
This paper describes the design goals and engineering efforts that led to the realization of AMBER (Astronomical Multi BEam combineR) and to the achievement of its present performa…
Reversal-free CaIIH profiles: a challenge for solar chromosphere modeling in quiet inter-network
R. Rezaei, J. H. M. J. Bruls, W. Schmidt +3
We study chromospheric emission to understand the temperature stratification in the solar chromosphere. We observed the intensity profile of the CaIIH line in a quiet Sun region cl…
Calculation of Spectral Darkening and Visibility Functions for Solar Oscillations
C. Nutto, M. Roth, Y. Zhugzhda +2
Calculations of spectral darkening and visibility functions for the brightness oscillations of the Sun resulting from global solar oscillations are presented. This has been done fo…
Do Long-Lived Features Really Exist in the Solar Photosphere? II. Contrast of Time-Averaged Granulation Images
P. N. Brandt, A. V. Getling
The decrease in the rms contrast of time-averaged images with the averaging time is compared between four datasets: (1) a series of solar granulation images recorded at La Palma in…
The horizontal internetwork magnetic field: numerical simulations in comparison to observations with Hinode
O. Steiner, R. Rezaei, W. Schaffenberger +1
Observations with the Hinode space observatory led to the discovery of predominantly horizontal magnetic fields in the photosphere of the quiet internetwork region. Here we investi…
A 3-D sunspot model derived from an inversion of spectropolarimetric observations and its implications for the penumbral heating
C. Beck
I deduced a 3-D sunspot model that is in agreement with spectropolarimetric observations, to address the question of penumbral heating by the repetitive rise of flow channels. I pe…
The signature of chromospheric heating in Ca II H spectra
C. Beck, W. Schmidt, R. Rezaei +1
We analyze a 1-hour time series of Ca II H intensity spectra and polarimetric spectra around 630 nm to derive the signature of the chromospheric heating and to investigate its rela…
Freeware solutions for spectropolarimetric data reduction
F. Paletou, R. Rezaei, L. Leger
Most of the solar physicists use very expensive software for data reduction and visualization. We present hereafter a reliable freeware solution based on the Python language. This…
Hinode observations reveal boundary layers of magnetic elements in the solar photosphere
R. Rezaei, O. Steiner, S. Wedemeyer-Böhm +3
We study the structure of the magnetic elements in network-cell interiors. A quiet Sun area close to the disc centre was observed with the spectro-polarimeter of the Solar Optical…
The Fine-Structure of the Net-Circular Polarization in a Sunspot Penumbra
A. Tritschler, D. A. N. Mueller, R. Schlichenmaier +1
We present novel evidence for a fine structure observed in the net-circular polarization (NCP) of a sunspot penumbra based on spectropolarimetric measurements utilizing the Zeeman…
Meridional Circulation and Global Solar Oscillations
Markus Roth, Michael Stix
We investigate the influence of large-scale meridional circulation on solar p-modes by quasi-degenerate perturbation theory, as proposed by \cite{lavely92}. As an input flow we use…
Observations and modeling of the early acceleration phase of erupting filaments involved in coronal mass ejections
C. J. Schrijver, C. Elmore, B. Kliem +2
We examine the early phases of two near-limb filament destabilization involved in coronal mass ejections on 16 June and 27 July 2005, using high-resolution, high-cadence observatio…
The solar chromosphere at high resolution with IBIS. I. New insights from the Ca II 854.2 nm line
G. Cauzzi, K. P. Reardon, H. Uitenbroek +7
(Abridged) Aims: In this paper, we seek to establish the suitability of imaging spectroscopy performed in the Ca II 854.2 nm line as a means to investigate the solar chromosphere a…
Photospheric processes and magnetic flux tubes
O. Steiner
In the first part of these lecture notes, new high-resolution observations of small-scale magnetic flux concentrations are presented and compared to results from new three-dimensio…
Chromospheric Dynamics and Line Formation
R. Hammer, P. Ulmschneider
The solar chromosphere is very dynamic, due to the presence of large amplitude hydrodynamic waves. Their propagation is affected by NLTE radiative transport in strong spectral line…
Magnetic properties of G-band bright points in a sunspot moat
C. Beck, L. R. Bellot Rubio, R. Schlichenmaier +1
We present simultaneous spectropolarimetric observations of four visible and three infrared spectral lines from the VTT (Tenerife), together with speckle-reconstructed filtergrams…
Inter-network regions of the Sun at millimetre wavelengths
S. Wedemeyer-Boehm, H. -G. Ludwig, M. Steffen +2
The continuum intensity at wavelengths around 1 mm provides an excellent way to probe the solar chromosphere. Future high-resolution millimetre arrays, such as the Atacama Large Mi…
Opposite magnetic polarity of two photospheric lines in single spectrum of the quiet Sun
R. Rezaei, R. Schlichenmaier, W. Schmidt +1
We study the structure of the photospheric magnetic field of the quiet Sun by investigating weak spectro-polarimetric signals. We took a sequence of Stokes spectra of the Fe I 630.…
Numerical simulations of fast and slow coronal mass ejections
T. Toeroek, B. Kliem
Solar coronal mass ejections (CMEs) show a large variety in their kinematic properties. CMEs originating in active regions and accompanied by strong flares are usually faster and a…
Sensitivity of low degree oscillations to the change in solar abundances
A. Zaatri, J. Provost, G. Berthomieu +2
Context. The most recent determination of the solar chemical composition, using a time-dependent, 3D hydrodynamical model of the solar atmosphere, exhibits a significant decrease o…
Planets around active stars
J. Setiawan, P. Weise, Th. Henning +8
We present the results of radial velocity measurements of two samples of active stars. The first sample contains field G and K giants across the Red Giant Branch, whereas the secon…
Modeling the (upper) solar atmosphere including the magnetic field
H. Peter
The atmosphere of the Sun is highly structured and dynamic in nature. From the photosphere and chromosphere into the transition region and the corona plasma- changes from above…