Browsing Institutt for teoretisk astrofysikk by Title

Now showing items 333-352 of 1278

  • Discretisation of the angular two-point correlation function 
    Selmer, Benedicte (Master thesis / Hovedoppgave, 2003)
    Through the two-point correlation function the effects of limited sky coverage and discretisation of data on satellite observations of the cosmic microwave background (CMB) is examined. Analytical expressions for the ...
  • Disentangling flows in the solar transition region 
    Zacharias, Pia; Hansteen, Viggo; Leenaarts, Jorrit; Carlsson, Mats; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: The measured average velocities in solar and stellar spectral lines formed at transition region temperatures have been difficult to interpret. The dominant redshifts observed in the lower transition region naturally ...
  • Dissecting bombs and bursts: Non-LTE inversions of low-atmosphere reconnection in SST and IRIS observations 
    Vissers, Gregal Joan Maria; de la Cruz Rodriguez, Jaime; Libbrecht, Tine; Rouppe van der Voort, Luc; Scharmer, Göran B.; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Ellerman bombs and UV bursts are transient brightenings that are ubiquitously observed in the lower atmospheres of active and emerging flux regions. As they are believed to pinpoint sites of magnetic reconnection in ...
  • Distinguishing between gravity theories with galaxy peculiar velocity statistics 
    Fauli, Robert Olav (Master thesis / Masteroppgave, 2015)
    The ΛCDM model used in modern cosmology has major theoretical problems. To attempt to solve these many modified gravity theories have been proposed. We calculate velocity statistics (streaming pair-wise velocities and the ...
  • Distinguishing screening mechanisms with environment-dependent velocity statistics 
    Ivarsen, Magnus Fagernes (Master thesis / Masteroppgave, 2016)
  • Diversity in extinction laws of Type Ia supernovae measured between 0.2 and 2 μm 
    Amanullah, R.; Johansson, J.; Goobar, A.; Ferretti, R.; Papodogiannakis, S.; Petrushevska, T.; Brown, P. J.; Cao, Y.; Contreras, C.; Dahle, Håkon; Elias-Rosa, N.; Fynbo, J. P. U.; Gorosabel, J.; Guaita, L.; Hangard, L.; Howell, D. A.; Hsiao, E. Y.; Kankare, E.; Kasliwal, M.; Leloudas, G.; Lundqvist, P.; Mattila, S.; Nugent, P.; Phillips, M. M.; Sandberg, A.; Stanishev, V.; Sullivan, M.; Taddia, F.; Östlin, G.; Asadi, S.; Herrero-Illana, R.; Jensen, J. J.; Karhunen, K.; Lazarevic, S.; Varenius, E.; dos Santos, Paulo Guilherme; Seethapuram Sridhar, S.; Wallström, S. H. J.; Wiegert, J. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations ...
  • Do we have any hope of detecting scattering between dark energy and baryons through cosmology? 
    Vagnozzi, Sunny; Visinelli, Luca; Mena, Olga; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    We consider the possibility that dark energy and baryons might scatter off each other. The type of interaction we consider leads to a pure momentum exchange, and does not affect the background evolution of the expansion ...
  • Does a generalized Chaplygin gas correctly describe the cosmological dark sector? 
    vom Marttens, Rodrigo F.; Casarini, Luciano; Zimdahl, Winfried; Hipólito-Ricaldi, William S.; Mota, David (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2017)
    vom Marttens, R. F., et al. "Does a generalized Chaplygin gas correctly describe the cosmological dark sector?." Physics of the Dark Universe 15 (2017): 114-124. © 2017. This manuscript version is made available under the ...
  • Domain walls coupled to matter: The symmetron example 
    Llinares, Claudio; Pogosian, Levon (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    We study properties of domain walls in the symmetron model, in which the scalar gravitational degree of freedom decouples from matter in regions of high density and exhibits a spontaneously broken Z2 symmetry at low ...
  • Down-the-barrel observations of a multi-phase quasar outflow at high redshift: VLT/X-shooter spectroscopy of the proximate molecular absorber at z = 2.631 towards SDSS J001514+184212 
    Noterdaeme, Pasquier; Balashev, S.; Krogager, J.-K.; Laursen, Peter; Srianand, R.; Gupta, N.; Petitjean, Patrick; Fynbo, Johan P. U. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    We present ultraviolet to near infrared spectroscopic observations of the quasar SDSS J001514+184212 and its proximate molecular absorber at z = 2.631. The [O III] emission line of the quasar is composed of a broad (FWHM ...
  • Downflowing umbral flashes as evidence of standing waves in sunspot umbrae 
    Felipe, Tobias; de Jorge Henriques, Vasco Manuel; de la Cruz Rodriguez, Jaime; Socas-Navarro, Hector (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Context. Umbral flashes are sudden brightenings commonly visible in the core of some chromospheric lines. Theoretical and numerical modeling suggests that they are produced by the propagation of shock waves. According to ...
  • Download by parachute: retrieval of assets from high altitude balloons 
    Sirks, Ellen L.; Clark, P.; Massey, Richard J.; Benton, S. J.; Brown, A. M.; Damaren, Christopher J.; Eifler, Tim; Fraisse, Aurélien A.; Frenk, Carlos; Funk, M.; Galloway, Mathew; Gill, Ajay; Hartley, John W.; Holder, Bradley; Huff, Eric M.; Jauzac, Mathilde; Jones, William C.; Lagattuta, David; Leung, Jason S.-Y.; Li, L.; Luu, Thuy Vy T.; McCleary, Jacqueline; Netterfield, Calvin Barth; Redmond, S.; Rhodes, Jason D.; Romualdez, L. Javier; Schmoll, Jürgen; Shaaban, Mohamed M.; Tam, Sut-Ieng (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    We present a publicly-available toolkit of flight-proven hardware and software to retrieve 5 TB of data or small physical samples from a stratospheric balloon platform. Before launch, a capsule is attached to the balloon, ...
  • Dramatic Changes in the Observed Velocity of the Accretion Disk Wind in MCG-03-58-007 Are Revealed by XMM-Newton and NuSTAR 
    Braito, Valentina; Reeves, J.N.; Matzeu, Gabriele A.; Severgnini, Paola; Ballo, Lucia; Cicone, Claudia; Ceca, R. Della; Giustini, M.; Sirressi, Mattia (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Past X-ray observations of the nearby Seyfert 2 MCG-03-58-007 revealed the presence of a powerful and highly variable disk wind, where two possible phases outflowing with vout1/c ∼ −0.07 and vout2/c ∼ −0.2 were observed. ...
  • Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): insights from the dark energy survey deep fields 
    Burke, Colin J.; Liu, Xin; Shen, Yue; Phadke, Kedar A.; Yang, Qian; Hartley, William G.; Harrison, Ian; Palmese, Antonella; Hengxiao, Guo; Zhang, Kaiwen; Kron, Richard; Turner, David J.; Giles, Paul A.; Lidman, Christopher; Chen, Yu-Ching; Gruendl, Robert A.; Choi, Ami; Amon, Alexandra; Sheldon, Erin; Aguena, M.; Allam, Sahar; Andrade-Oliveira, Felipe; Bacon, D.; Bertin, E.; Brooks, D.; Carnero Rosell, Aurelio; Carrasco Kind, Matias; Carretero, J.; Conselice, Christopher; Costanzi, M.; da Costa, Luiz N.; Pereira, Maria Elidaiana da Silva; Davis, Tamara M.; De Vicente, J.; Desai, S.; Diehl, Herman T.; Everett, S.; Ferrero, Ismael; Flaugher, B.; García-Bellido, J.; Gaztañaga, Enrique; Gruen, D.; Gschwend, J.; Gutierrez, G.; Hinton, Samuel R.; Hollowood, Devon L.; Honscheid, K.; Hoyle, B.; James, D. J.; Kuehn, K.; Maia, M. A. G.; Marshall, Jennifer L.; Menanteau, F.; Miquel, R.; Morgan, R.; Paz-Chinchón, Francisco; Pieres, A.; Plazas Malagón, Andrés A.; Reil, K.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, Ignacio; Smith, Mathew; Suchyta, E.; Tarle, G.; Thomas, D.; To, Chun-Hao; Varga, Tamas Norbert; Wilkinson, R. D. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    We present a sample of 706, z < 1.5 active galactic nuclei (AGNs) selected from optical photometric variability in three of the Dark Energy Survey (DES) deep fields (E2, C3, and X3) over an area of 4.64 deg2. We construct ...
  • Dynamic Loops in a Solar Active Region 
    Emblemsvåg, Geir (Master thesis / Hovedoppgave, 2007)
  • Dynamic properties along the neutral line of a delta spot inferred from high-resolution observations 
    Cristaldi, A.; Guglielmino, S. L.; Zuccarello, F.; Romano, P.; Falco, M.; Rouppe, Van Der Voort Luc; de la Cruz Rodriguez, Jaime; Ermolli, I.; Criscuoli, S. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    Delta (δ) spots are complex magnetic configurations of sunspots characterized by umbrae of opposite polarity sharing a common penumbra. In order to investigate the fine structure of the region separating the two magnetic ...
  • Dynamical friction on hot bodies in gaseous, opaque media, and application to embedded protoplanets 
    Masset, F.S.; Velasco Romero, D.A.; Eklund, Lars Henrik (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    A massive and luminous perturber moving across an opaque gas is subjected to a force different from the gravitational friction that it would experience if it were cold. The heat released by the perturber diffuses in the ...
  • Dynamics of fine structure in the atmosphere of solar active regions 
    Vissers, Gregal Joan Maria (Doctoral thesis / Doktoravhandling, 2013)
    This thesis presents an observational study of the dynamics of fine structure in the (mostly lower) atmosphere of solar active regions. The considered phenomena – Ellerman bombs, flocculent flows and coronal rain – are ...
  • Dynamics of internetwork chromospheric fibrils: Basic properties and magnetohydrodynamic kink waves 
    Mooroogen, K.; Morton, R. J.; de Jorge Henriques, Vasco Manuel (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Aims. Current observational instruments are now providing data with the necessary temporal and spatial cadences required to examine highly dynamic, fine-scale magnetic structures in the solar atmosphere. Using the spectroscopic ...
  • Dynamics of Large-Scale Solar Flows 
    Hotta, Hideyuki; Bekki, Yuto; Gizon, Laurent; Noraz, Quentin Jean Francois Alain; Rast, Mark (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Abstract The Sun’s axisymmetric large-scale flows, differential rotation and meridional circulation, are thought to be maintained by the influence of rotation on the thermal-convective motions in the solar convection zone. ...