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Pandit, Sneha; Wedemeyer, Sven & Carlsson, Mats
(2023).
Comparison of activity indicators in a 3D model atmosphere.
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Wedemeyer, Sven & Szydlarski, Mikolaj
(2023).
Artificial observations of the Sun – The scientific potential of optimizing future solar observatories.
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Wedemeyer, Sven
(2023).
Radio and millimeter observations of the Sun - Recent advances and future opportunities .
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Wedemeyer, Sven & Kirkaune, Mats
(2023).
Observing the Sun with AtLAST - Prospects and Challenges.
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Pandit, Sneha; Wedemeyer, Sven & Carlsson, Mats
(2023).
Comparison of activity indicators in a 3D model atmosphere
.
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Wedemeyer, Sven; Sand, Mats Ola; Øyre, Eilif Sommer & D`Angelo, Martina
(2022).
På jakt etter eksoplaneter .
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Guevara Gomez, Juan Camilo; Jafarzadeh, Shahin & Wedemeyer, Sven
(2022).
Characterisation of bright chromospheric and oscillating small-scale features observed with ALMA.
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Mohan, Atul; Wedemeyer, Sven; Oberoi, Divya; Hauschildt, Peter, H.; McCauley, Patrick & Mondal, Surajit
[Show all 9 contributors for this article]
(2022).
New insights on solar/stellar activity using the tomographic potential of mm & radio spectroscopic imaging.
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Pandit, Sneha; Wedemeyer, Sven & Mohan, Atul
(2022).
Formation of Activity Indicators in a 3D model atmosphere.
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Mohan, Atul; Wedemeyer, Sven; Hauschildt, Peter, H.; Pandit, Sneha & Saberi, Maryam
(2022).
Stellar atmospheric tomography with mm - cm spectroscopic imaging.
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Mohan, Atul; Wedemeyer, Sven; Pandit, Sneha; Saberi, Maryam & Hauschildt, Peter, H.
(2022).
A potential robust millimeter activity index & its links to atmospheric structure and physical parameters.
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Mohan, Atul; Oberoi, Divya; Wedemeyer, Sven; Mondal, Surajit; McCauley, Patrick & Mastrano, Alpha
[Show all 9 contributors for this article]
(2022).
Tomographic exploration of solar/stellar activity with modern radio & mm arrays.
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Pandit, Sneha; Wedemeyer, Sven & Mohan, Atul
(2022).
The Formation of Activity Indicators in 3D Model Atmosphere.
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Pandit, Sneha; Wedemeyer, Sven & Mohan, Atul
(2022).
Formation of Activity Indicators in a 3D model Atmosphere.
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Pandit, Sneha; Wedemeyer, Sven & Carlsson, Mats
(2022).
Formation of Activity Indicators in a 3D Model Atmosphere.
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Saberi, Maryam; Khouri, T.; Velilla-Prieto, L.; Fonfria, J. P.; Vlemmings, W. & Wedemeyer, Sven
(2022).
Tracing the role of AGB stars in the Galactic Fluorine budget .
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Guevara Gomez, Juan Camilo; Jafarzadeh, Shahin & Wedemeyer, Sven
(2021).
Oscillations in chromospheric small-scale bright features observed with ALMA.
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Saberi, Maryam; Khouri, Theo; Velilla-Prieto, L.; Fonfria, . P.; Vlemmings, W. & Wedemeyer, Sven
(2021).
Tracing the role of AGB stars in the Galactic Fluorine budget .
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Wedemeyer, Sven; Szydlarski, Mikolaj; Jafarzadeh, Shahin; Henriques, Vasco; Guevara Gomez, Juan Camilo & Eklund, Henrik
[Show all 10 contributors for this article]
(2021).
Lessons learned from 5 years of solar observing with ALMA.
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Wedemeyer, Sven; Szydlarski, Mikolaj; Jafarzadeh, Shahin; Henriques, Vasco; Eklund, Henrik & Guevara Gomez, Juan Camilo
[Show all 11 contributors for this article]
(2021).
A brief introduction to solar observing with ALMA .
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Wedemeyer, Sven; Szydlarski, Mikolaj; Jafarzadeh, Shahin; Henriques, Vasco; Eklund, Henrik & Guevara Gomez, Juan Camilo
[Show all 10 contributors for this article]
(2021).
Five years observing the solar chromosphere with ALMA - First results and future opportunities.
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Guevara Gomez, Juan Camilo; Jafarzadeh, Shahin & Wedemeyer, Sven
(2021).
Oscillations in small-scale bright features observed with ALMA.
Show summary
Small-scale chromospheric bright features in a plage/enhanced network are identified in solar ALMA observations. The features present oscillations in brightness temperature, size and horizontal velocity. Interestingly, an anti-correlation between brightness temperature and size is also evident, suggesting that these features might be associated to fast-sausage MHD modes. A statistical analysis is carried out to quantify the oscillation periods of the three quantities and the phase angles between the perturbations in temperature and size. The values found are in agreement with periods of high frequency oscillations in other layers of the solar atmosphere.
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Guevara Gomez, Juan Camilo & Wedemeyer, Sven
(2021).
Dynamics of small-scale dark features observed by the Atacama Large Millimeter/Submillimeter Array (ALMA).
Show summary
Observations of the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA) now allow for more quantitative determination of temperatures in the chromosphere. ALMA observations of Quiet Sun regions in receiver Band 3 (3 mm; 100 GHz) exhibit small-scale features that resemble a mesh-like chromospheric pattern, similar to what was earlier detected with other chromospheric diagnostics. Tracking the features in time results in lifetimes, velocities and sizes, which are analysed within the context given by co-aligned images of the Solar Dynamics Observatory (SDO). Here we present a statistical analysis and compare the results with a 3D MHD simulation with Bifrost of an enhanced network which has been degraded to the ALMA spatial resolution. The match between observations and simulations suggests that the dark features are post-shock regions. The thermodynamics and kinetic properties derived from the ALMA observations will therefore enhance our understanding of the small-scale dynamics and heating of the solar chromosphere and its potential implications for other solar-like stars.
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Saberi, Maryam; Jafarzadeh, Shahin; Gafeira, Ricardo; Wedemeyer, Sven & Szydlarski, Mikolaj
(2021).
MHD waves in chromospheric fibrillar structures as observed with ALMA.
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Wedemeyer, Sven
(2021).
Sola over Atacama-ørkenen.
Astronomi.
ISSN 0802-7587.
2,
p. 36–39.
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Jafarzadeh, Shahin; Gafeira, Ricardo; Wedemeyer, Sven & Szydlarski, Mikolaj
(2021).
MHD waves in chromospheric fibrillar structures as observed with ALMA.
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Pandit, Sneha & Wedemeyer, Sven
(2021).
The sun as a star: new insights from the full disk observations with ALMA.
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Wedemeyer, Sven; Szydlarski, Mikolaj; Jafarzadeh, Shahin; de Jorge Henriques, Vasco Manuel; Eklund, Henrik & Guevara Gomez, Juan Camilo
[Show all 10 contributors for this article]
(2021).
Observing the Sun with ALMA - First results and future opportunities.
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Wedemeyer, Sven; Szydlarski, Mikolaj; Jafarzadeh, Shahin; de Jorge Henriques, Vasco Manuel; Eklund, Henrik & Guevara Gomez, Juan Camilo
[Show all 10 contributors for this article]
(2021).
Five years observing the solar chromosphere with ALMA - First results and future opportunities.
-
Guevara Gomez, Juan Camilo & Wedemeyer, Sven
(2021).
Dynamics of small-scale dark features observed by the Atacama Large Millimeter/submillimeter Array (ALMA).
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White, Stephen; Barta, Miroslav; Bastian, Timothy; Shimojo, Masumi & Wedemeyer, Sven
(2020).
Correlator Desiderata for Solar Radiophysics at ALMA.
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Eklund, Henrik; Szydlarski, Mikolaj Marcin & Wedemeyer, Sven
(2020).
Image reconstruction of interferometric ALMA data.
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Wedemeyer, Sven
(2020).
Development of tools for solar research with ALMA at RoCS.
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Wedemeyer, Sven
(2020).
Observing the Sun with ALMA – Challenges, scientific potential, and first results.
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Wedemeyer, Sven
(2020).
Magnetic Tornadoes on the Sun.
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Wedemeyer, Sven
(2019).
Magnetic Field Measurements with the Atacama Millimeter/submillimeter Array.
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Wedemeyer, Sven
(2019).
Solar science with ALMA in Norway.
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Wedemeyer, Sven
(2019).
High-tech and llamas.
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Wedemeyer, Sven
(2019).
High-cadence imaging of the Sun
.
Show summary
A challenge of observing the Sun with ALMA is that the primary beam covers only a small region on the Sun and is therefore filled with a complex radiation pattern, which evolves on extremely short time scales of only seconds and below. Fully exploiting ALMA's possibilities therefore requires imaging at very high cadence. Accordingly, there is much potential for improving the solar observing modes and post-processing of data. The development study "High-cadence imaging of the Sun", which started in 2018, aims at developing a high-cadence imaging capability by employing realistic test cases based on state-of-the-art numerical simulations, the Solar ALMA Simulator tool, and a solar simulation pipeline. Comparisons between the input and output of the simulation pipeline will reveal how well imaging at high cadence performs and how to optimize it. We present an overview of the study and its current state.
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Wedemeyer, Sven
(2019).
Solar Astronomy with ALMA
.
Show summary
Solar observing with ALMA is offered as a non-standard mode since Cycle 4. The requirements for such observations are different from many other observations with ALMA in the sense that the mapped atmospheric layers of the Sun evolve on very short timescales and the primary beam being filled with complex emission. High-cadence (snapshot) imaging is needed for such a dynamic target but is very challenging. The effort and time that went into developing the observing mode seems well justified given that ALMA provides a new complementary view at a part of the solar atmosphere that is still elusive in many aspects. The solar observing campaigns with ALMA are co-ordinated with a number of space-borne and ground-based telescopes covering the UV to IR range. Co-ordinating such strictly simultaneous multi-telescope observations adds another layer of complexity but results in rich data sets covering all layers of the solar atmosphere while probing different properties of the atmospheric gas. Since Cycle 4, the imaging procedures for solar ALMA observations have been significantly improved and science-ready data are being produced. I will give a brief overview over ALMA's diagnostic potential for the Sun and challenges with carrying out solar observations and post-processing the data. First examples for Band 3 and Band 6 data are presented and illustrate the dynamic nature of the solar atmosphere, featuring, among other things, the imprint of magnetic fields and propagating shock waves.
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Jafarzadeh, Shahin; Wedemeyer, Sven; Noda, Carlos Quintero; Wiegelmann, Thomas & Rouppe van der Voort, Luc
(2019).
Magnetic-field topology throughout the solar chromosphere.
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Jafarzadeh, Shahin; Wedemeyer, Sven; Szydlarski, Mikolaj Marcin; Fleck, Bernhard & Stangalini, Marco
(2019).
Wave heating of the solar chromosphere from observations with ALMA.
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Jafarzadeh, Shahin; Wedemeyer, Sven; Szydlarski, Mikolaj Marcin & Fleck, Bernhard
(2019).
Wave heating of the lower solar atmosphere.
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Jafarzadeh, Shahin; van der Voort, Luc H.M. Rouppe; Wedemeyer, Sven & Noda, Carlos Quintero
(2019).
Magnetic-field topology of fibrillar structures throughout the solar chromosphere.
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Jafarzadeh, Shahin; Wedemeyer, Sven & Szydlarski, Mikolaj Marcin
(2019).
Temperature Fluctuations in the Solar Chromosphere with ALMA.
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Jafarzadeh, Shahin & Wedemeyer, Sven
(2019).
Observing Waves in the Lower Solar Atmosphere with ALMA.
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Eklund, Henrik; Szydlarski, Mikolaj Marcin & Wedemeyer, Sven
(2019).
Shock wave propagation with high cadence solar ALMA time series.
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Guevara Gomez, Juan Camilo; Wedemeyer, Sven; Jafarzadeh, Shahin & Szydlarski, Mikolaj Marcin
(2019).
Dynamics of solar isolated features observed by the Atacama Large Millimeter/submillimeter Array (ALMA).
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Guevara Gomez, Juan Camilo; Wedemeyer, Sven; Jafarzadeh, Shahin & Szydlarski, Mikolaj Marcin
(2019).
Structure and dynamics of isolated features in the solar chromosphere observed with ALMA.
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Wedemeyer, Sven
(2019).
Our Dynamic Sun.
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Eklund, Henrik; Szydlarski, Mikolaj Marcin & Wedemeyer, Sven
(2018).
Interferometric ALMA observations and data processing.
-
Wedemeyer, Sven
(2018).
Experiences from applying for an ERC Consolidator Grant.
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Wedemeyer, Sven
(2018).
Oppvarming av solens atmosfære & solfysikkforskning i dag.
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Wedemeyer, Sven
(2018).
Sola, din nærmeste stjerne
.
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Wedemeyer, Sven
(2018).
Solar Observations with ALMA.
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Wedemeyer, Sven
(2015).
Rød sol og evig daggry: Leting etter liv på fjerne kloder.
In Kristiansen, Jostein Riiser; Evans, Anna Kathinka Dalland; Svensen, Henrik; Samset, Bjørn Hallvard & Byhring, Hanne Sigrun (Ed.),
Stjerneklart – siste nytt fra verdensrommet.
Spartacus.
ISSN 9788243009738.
p. 96–108.
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Ayres, T. R.; Lyons, J. R.; Ludwig, Hans-Günter; Caffau, E. & Wedemeyer-Böhm, Sven
(2013).
Isotopic CO in the Solar Photosphere, Viewed Through the Lens of 3D Spectrum Synthesis.
-
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Kjeldseth-Moe, Olav & Wedemeyer-Böhm, Sven
(2009).
Are there variations in Earth’s global mean temperature related to the solar activity?
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Rezaei, Rezza; Steiner, Oskar; Wedemeyer-Böhm, Sven; Schlichenmaier, Rolf & Lites, Bruce W.
(2007).
Variation of the Stokes-V area asymmetry across magnetic elements.
Astronomical Notes - Astronomische Nachrichten.
ISSN 0004-6337.
328(7).
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Wedemeyer-Böhm, Sven
(2007).
Small-scale structure and dynamics of the lower solar atmosphere.
-
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Guevara Gomez, Juan Camilo; Wedemeyer, Sven & Rouppe van der Voort, Luc
(2022).
Observations of the dynamics and structure of the solar atmosphere with ALMA .
Universitetet i Oslo.
ISSN 1501-7710.
-
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Gaudi, Scott; Blackwood, Gary; Howard, Andrew; Latham, David; Fischer, Debra & Wedemeyer, Sven
(2019).
Extreme Precision Radial Velocity (EPRV) Working Group.
Bulletin of the American Astronomical Society.
