Now showing items 480-499 of 516

  • Jønvik, Sara Clausen (Master thesis / Masteroppgave, 2017)
    We perform an investigation of quadru- and octopolar asymmetry in the CMB data by expanding the on the study of alignment and angular clustering of the dipole components of the CMB power distribution across multipoles l = ...
  • Chakrabarti, Sukanya; Chang, Philip; O'Shaughnessy, Richard; Brooks, Alyson M.; Shen, Sijing; Bellovary, Jillian; Gladysz, Wojciech; Belczynski, Chris (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We investigate the contribution of outer H i disks to the observable population of merging black hole binaries. Like dwarf galaxies, the outer H i disks of spirals have low star formation rates and lower metallicities than ...
  • Keys, Peter H.; Reid, Aaron; Mathioudakis, Mihalis; Shelyag, Sergiy; de Jorge Henriques, Vasco Manuel; Hewitt, Rebecca L.; Del Moro, Dario; Jafarzadeh, Shahin; Jess, David B.; Stangalini, Marco (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Magnetic bright points (MBPs) are small-scale magnetic elements ubiquitous across the solar disc, with the prevailing theory suggesting that they form due to the process of convective collapse. Employing a unique full ...
  • hong, Jie; Li, Ying; Ding, M. D.; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The solar Lyα line is the strongest line in the ultraviolet waveband, and is greatly enhanced during solar flares. Here we present radiative hydrodynamic simulations of solar flares under different heating models, and ...
  • Hagala, Robert; Llinares, Claudio; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Context: There are currently no reliable methods to measure the transverse velocities of galaxies. This is an important piece of information that is lacking in galaxy catalogues, and it could allow us to probe the physics ...
  • Herman, Daniel Christopher (Master thesis / Masteroppgave, 2019)
  • Wedemeyer, Sven; Kučinskas, Arūnas; Klevas, Jonas; Ludwig, Hans-Günter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Aims. Although observational data unequivocally point to the presence of chromospheres in red giant stars, no attempts have been made so far to model them using 3D hydrodynamical model atmospheres. We therefore compute an ...
  • Bjørgen, Johan pires; Sukhorukov, Andrii V.; Leenaarts, Jorrit; Carlsson, Mats; de la Cruz Rodriguez, Jaime; Scharmer, Göran B.; Hansteen, Viggo (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: CHROMIS, a new imaging spectrometer at the Swedish 1-m Solar Telescope (SST), can observe the chromosphere in the H and K lines of Ca II at high spatial and spectral resolution. Accurate modeling as well as an ...
  • Stepan, J.; Trujillo Bueno, J.; Leenaarts, Jorrit; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    Probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in UV spectral lines. Here we apply PORTA ( a novel radiative ...
  • Dahle, Håkon; Gladders, M. D.; Sharon, K.; Bayliss, M. B.; Rigby, J. R. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    We report fi rst results from an ongoing monitoring campaign to measure time delays between the six images of the quasar SDSS J2222 + 2745, gravitationally lensed by a galaxy cluster. The time delay between A and B, the ...
  • Dyrland, Karianne (Master thesis / Masteroppgave, 2019)
  • Martinez-Sykora, Juan; De Pontieu, Bart Walter; Hansteen, Viggo; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    The properties of nonstatistical equilibrium ionization of silicon and oxygen ions are analyzed in this work. We focus on five solar targets (quiet Sun; coronal hole; plage; quiescent active region, AR; and flaring AR) as ...
  • Mouland, Maria (Master thesis / Masteroppgave, 2009)
    I have investigated the total energy of Friedmann-Robertson-Walker universes. This is an interesting issue, because if the energy of the universe turns out not to be conserved, it will be in conflict with our common ...
  • Eide, Marius Berge (Master thesis / Masteroppgave, 2015)
  • Biswas, T.; Gerwick, E.; Koivisto, Tomi Sebastian; Mazumdar, A. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    We present the most general covariant ghost-free gravitational action in a Minkowski vacuum. Apart from the much studied f(R) models, this includes a large class of nonlocal actions with improved UV behavior, which ...
  • Christensen, Charlotte R.; Davé, Romeel; Brooks, Alyson M.; Quinn, Thomas; Shen, Sijing (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    We analyze the metal accumulation in dwarf and spiral galaxies by following the history of metal enrichment and outflows in a suite of 20 high-resolution simulated galaxies. These simulations agree with the observed stellar ...
  • Groeneboom, Nicolaas Ervik (Master thesis / Masteroppgave, 2007)
  • Jafarzadeh, Shahin; Solanki, S. K.; Gafeira, Ricardo; van Noort, M.; Barthol, P.; Blanco Rodriguez, J.; del Toro Iniesta, J. C.; Gandorfer, A.; Gizon, L; Hirzberger, J.; Knölker, M.; Orozco Suarez, D.; Riethmüller, T. L.; Schmidt, W. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We present observations of transverse oscillations in slender Ca ii H fibrils (SCFs) in the lower solar chromosphere. We use a 1 hr long time series of high- (spatial and temporal-) resolution seeing-free observations in ...
  • Antolin, Patrick; Schmit, D.; Pereira, Tiago Mendes Domingos; De Pontieu, Bart Walter; De Moortel, I. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    In addition to their jet-like dynamic behavior, spicules usually exhibit strong transverse speeds, multi-stranded structure, and heating from chromospheric to transition region temperatures. In this work we first analyze ...
  • Martinez-Sykora, Juan; De Pontieu, Bart Walter; Carlsson, Mats; Hansteen, Viggo; Nobrega-Siverio, Daniel; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code. We have extended the code capabilities implementing ...