Browsing Institutt for teoretisk astrofysikk by Title
Now showing items 360-379 of 1278
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)We study the effect of the cubic torus topology of the Universe on scalar cosmological perturbations which define the gravitational potential. We obtain three alternative forms of the solution for both the gravitational ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)We study a novel interacting dark energy − dark matter scenario where the anisotropic stress of the large-scale inhomogeneities is considered. The dark energy has a constant equation of state and the interaction model ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)© 2017 American Physical Society
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)Context. Small-scale processes are thought to be important for the dynamics of the solar atmosphere. While numerical resolution fundamentally limits their inclusion in magnetohydronamic (MHD) simulations, real observations ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)Spicules have been observed on the Sun for more than a century, typically in chromospheric lines such as Hα and Ca II H. Recent work has shown that so-called "type II" spicules may have a role in providing mass to the ...
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(Master thesis / Masteroppgave, 2021)
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)The emergence of magnetic flux through the photosphere and into the outer solar atmosphere produces, amongst other dynamical phenomena, Ellerman bombs (EBs), which are observed in the wings of Hα and are due to magnetic ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)The emergence of magnetic flux through the photosphere and into the outer solar atmosphere produces, amongst other dynamical phenomena, Ellerman bombs (EBs), which are observed in the wings of Hα and are due to magnetic ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Context: Ellerman bombs (EBs), observed in the photospheric wings of the Hα line, and UV bursts, observed in the transition region Si IV line, are both brightenings related to flux emergence regions and specifically to ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)Ellerman bombs (EBs) are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)Ellerman bombs are transient brightenings of the wings of the solar Balmer lines that mark reconnection in the photosphere. Ellerman noted in 1917 that he did not observe such brightenings in the Na i D and Mg i b lines. ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)We study a granular-sized magnetic flux emergence event that occurred in NOAA 11024 in 2009 July. The observations were made with the CRISP spectropolarimeter at the Swedish 1 m Solar Telescope achieving a spatial resolution ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)Magnetic flux emergence into the outer layers of the Sun is a fundamental mechanism for releasing energy into the chromosphere and the corona. In this paper, we study the emergence of granular-sized flux concentrations and ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)We study, for the first time, the ascent of granular-sized magnetic bubbles from the solar photosphere through the chromosphere into the transition region and above. Such events occurred in a flux emerging region in NOAA ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)Context: An activity indicator, which can provide a robust quantitative mapping between the stellar activity and the physical properties of its atmosphere, is important in exploring the evolution of the observed active ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)Context. Due to their wide wavelength coverage across the millimeter to centimeter (mm–cm) range and their increased sensitivity, modern interferometric arrays facilitate observations of the thermal and non-thermal radiation ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Context. Nanoscale events in cooperation with steady heating from a slow heating mechanism, such as slow-burning current-sheets, could be able to heat the corona; however, their observational traces are hard to detect via ...
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(Master thesis / Masteroppgave, 2023)
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Accurate predictions for the nonlinear matter power spectrum are needed to confront theory with observations in current and near future weak-lensing and galaxy clustering surveys. We propose a computationally cheap method ...
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(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)Context. Densely packed coronal loops are rooted in photospheric plages in the vicinity of active regions on the Sun. The photospheric magnetic features underlying these plage areas are patches of mostly unidirectional ...