Now showing items 90-109 of 593

  • Lee, Eunseong (Master thesis / Masteroppgave, 2013)
    We investigate cosmologies where the accelerated expansion of the universe is driven by a fluid with an anisotropic equation of state. If dark energy equation of state is anisotropic, the expansion rate of the universe ...
  • L'Huillier, Benjamin; Winther, Hans Arnold; Mota, David; Park, Changbom; Kim, Juhan (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    We study the properties of dark matter haloes in a wide range of modified gravity models, namely, f(R), DGP and interacting dark energy models. We study the effects of modified gravity and dark energy on the internal ...
  • Yang, Weiqiang; Pan, Supriya; Vagnozzi, Sunny; Di Valentino, Eleonora; Mota, David; Capozziello, Salvatore (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)
    While the origin and composition of dark matter and dark energy remains unknown, it is possible that they might represent two manifestations of a single entity, as occurring in unified dark sector models. On the other hand, ...
  • Zumalacárregui, Miguel; Koivisto, Tomi Sebastian; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    It is shown that a disformally coupled theory in which the gravitational sector has the Einstein-Hilbert form is equivalent to a quartic Dirac-Born-Infeld Galileon Lagrangian, possessing nonlinear higher derivative ...
  • Seiff Ellewsen, Thor Andreas; Falck, Bridget Lynn; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    In order to determine the observable signatures of modified gravity theories, it is important to consider the effect of baryonic physics. We used a modified version of the ISIS code to run cosmological hydrodynamic simulations ...
  • Panopoulou, Georgia V.; Tassis, Konstantinos; Skalidis, Raphael; Blinov, Dmitriy; Liodakis, Ioannis; Pavlidou, Vasiliki; Potter, Stephen B.; Ramaprakash, Anamparambu N.; Readhead, Anthony C. S.; Wehus, Ingunn Kathrine (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The availability of large data sets with stellar distance and polarization information will enable a tomographic reconstruction of the (plane-of-the-sky-projected) interstellar magnetic field in the near future. We demonstrate ...
  • Holhjem, Karianne (Master thesis / Masteroppgave, 2006)
    Two galaxy clusters, Abell 1351 and Abell 1995, are examined using weak gravitational lensing techniques. Mass maps are created, and the clusters' density and shear profiles are compared to theoretical predictions. Gravitational ...
  • Neyrinck, Mark; Szapudi, Istvan; McCullagh, N.; Szalay, Alexander S; Falck, Bridget Lynn; Wang, Jie (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    The most common statistic used to analyse large-scale structure surveys is the correlation function, or power spectrum. Here, we show how ‘slicing’ the correlation function on local density brings sensitivity to interesting ...
  • Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out one-dimensional ...
  • Martinez-Sykora, Juan; De Pontieu, Bart Walter; Leenaarts, Jorrit; Pereira, Tiago Mendes Domingos; Carlsson, Mats; Hansteen, Viggo; Stern, J. V.; Tian, H; McIntosh, S.W.; Rouppe, Van Der Voort Luc (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    We have performed a three-dimensional radiative MHD simulation of the solar atmosphere. This simulation shows a jet-like feature that shows similarities to the type II spicules observed for the first time with Hinode's ...
  • Kooistra, Robin; Silva, Marta Bruno; Zaroubi, Saleem; Verheijen, Marc A. W.; Tempel, Elmo; Hess, Kelly M. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The intergalactic medium (IGM) plays an important role in the formation and evolution of galaxies. Recent developments in upcoming radio telescopes are starting to open up the possibility of making a first direct detection ...
  • Kleint, L.; Antolin, Patrick; Tian, H; Judge, Philip G.; Testa, Paola; De Pontieu, Bart Walter; Martinez-Sykora, Juan; Reeves, K. K.; Wuelser, J. P.; McKillop, S.; Saar, S.; Carlsson, Mats; Boerner, P.; Hurlburt, N.; Lemen, J.; Tarbell, T.D.; Title, A.; Golub, L.; Hansteen, Viggo; Jaeggli, S.; Kankelborg, C. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    Interface Region Imaging Spectrograph data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0farcs33. On 2013 August 30, we observed bursts of high Doppler shifts suggesting ...
  • Freij, N.; Scullion, Eamon; Nelson, C. J.; Mumford, S.; Wedemeyer-Böhm, Sven; Erdélyi, R. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    There have been ubiquitous observations of wave-like motions in the solar atmosphere for decades. Recent improvements to space- and ground-based observatories have allowed the focus to shift to smaller magnetic structures ...
  • Dahle, Håkon; Aghanim, Nabila; Guennou, L.; Hudelot, P.; Kneissl, R.; Pointecouteau, E.; Beelen, Anita; Bayliss, M; Douspis, M.; Nesvadba, N.; Hempel, A.; Gronke, Max Balthasar; Burenin, R.; Dole, H.; Harrison, Debbie; Mazzotta, P.; Sunyaev, R (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    As part of an all-sky follow-up of the Planck catalogue of Sunyaev-Zeldovich (SZ) cluster candidates detected in the first 14 months of data, we are observing cluster candidates in the southern sky in the optical imaging ...
  • Kano, R.; Trujillo Bueno, J.; Winebarger, A.; Auchère, F.; Narukage, N.; Ishikawa, R.; Kobayashi, K.; Bando, T.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Giono, G.; Hara, H.; Suematsu, Y.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.; Goto, M.; Belluzzi, L.; Stepan, Jiri; Asensio Ramos, A.; Manso Sainz, R.; Champey, P.; Cirtain, J.; De Pontieu, Bart Walter; Casini, R.; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    There is a thin transition region (TR) in the solar atmosphere where the temperature rises from 10,000 K in the chromosphere to millions of degrees in the corona. Little is known about the mechanisms that dominate this ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Ivarsen, Magnus Fagernes (Master thesis / Masteroppgave, 2016)