Browsing Institutt for teoretisk astrofysikk by Title

Now showing items 589-608 of 1279

  • In the realm of the Hubble tension—a review of solutions 
    Di Valentino, Eleonora; Mena, Olga; Pan, Supriya; Visinelli, Luca; Yang, Weiqiang; Melchiorri, Alessandro; Mota, David; Riess, Adam G.; Silk, Joseph (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
     The simplest ΛCDM model provides a good fit to a large span of cosmological data but harbors large areas of phenomenology and ignorance. With the improvement of the number and the accuracy of observations, discrepancies ...
  • An In-depth Study of the On-disc Counterpart to Type II Spicules 
    Sekse, Dan Henrik (Doctoral thesis / Doktoravhandling, 2013)
  • Indication of the Hanle Effect by Comparing the Scattering Polarization Observed by CLASP in the Lyα and Si III 120.65 nm Lines 
    Ishikawa, R.; Trujillo Bueno, J.; Uitenbroek, Han; Kubo, M.; Tsuneta, S.; Goto, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa, Y.; Ishikawa, S.; Giono, G.; Suematsu, Y.; Hara, H.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.; Auchère, F.; Stepan, Jiri; Belluzzi, L.; Asensio Ramos, A.; Manso Sainz, R.; De Pontieu, Bart Walter; Ichimoto, K.; Carlsson, Mats; Casini, R. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    The Chromospheric Lyman-Alpha Spectro-Polarimeter is a sounding rocket experiment that has provided the first successful measurement of the linear polarization produced by scattering processes in the hydrogen Lyα line ...
  • Indications for transit-timing variations in the exo-Neptune HAT-P-26b 
    von Essen, Carolina; Wedemeyer, Sven; Sosa, M. S.; Hjorth, M.; Parkash, V.; Freudenthal, J.; Mallonn, M.; Miculán, R. G.; Zibecchi, L.; Cellone, S.; Torres, A. F. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Upon its discovery, the low-density transiting Neptune HAT-P-26b showed a 2.1σ detection drift in its spectroscopic data, while photometric data showed a weak curvature in the timing residuals, the confirmation of which ...
  • Infalling gas in a Lyman-α blob 
    Ao, Yiping; Zheng, Zheng; Henkel, Christian; Nie, Shiyu; Alexandre, Beelen; Cen, Renyue; Dijkstra, Mark; Francis, Paul J.; Geach, James E.; Kohno, Kotaro; Lehnert, Matthew D.; Menten, Karl M.; Wang, Junzhi; Weiss, Axel (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    Lyman-α blobs (LABs) are spatially extended nebulae of emission in the Lyman-α (Lyα) line of hydrogen, seen at high redshifts and most commonly found in the dense environment of star-forming galaxies. A recent study showed ...
  • Instabilities appearing in cosmological effective field theories: when and how? 
    Eckmann, Jean-Pierre; Hassani, Farbod; Zaag, Hatem (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
  • Instrument Calibration of the Interface Region Imaging Spectrograph (IRIS) Mission 
    Wulser, J. P.; Jaeggli, S.; De Pontieu, Bart Walter; Tarbell, T; Boerner, P.; Freeland, S.; Liu, W.; Timmons, R.; Brannon, S; Kankelborg, C.; Madsen, C; McKillop, S.; Prchlik, J; Saar, S.; Schanche, N; Testa, P; Bryans, P.; Wiesmann, Martin (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    The Interface Region Imaging Spectrograph (IRIS) is a NASA small explorer mission that provides high-resolution spectra and images of the Sun in the 133 – 141 nm and 278 – 283 nm wavelength bands. The IRIS data are archived ...
  • Intensity and velocity oscillations in a flaring active region 
    Millar, David C.L.; Fletcher, Lyndsay; Joshi, Jayant (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    ABSTRACT Chromospheric oscillations can give us insight into the physical environment in the solar atmosphere, both in quiet Sun and flaring conditions. Many authors have reported increases in the prevalence of ...
  • Intensity Contrast as a Function of Underlying Magnetic Field Through the Solar Atmosphere 
    Kjelseth, Ingrid Marie Endresen (Master thesis / Masteroppgave, 2020)
  • Interaction of solar jets with filaments: Triggering of large-amplitude filament oscillations 
    Joshi, Reetika; Luna, Manuel; Schmieder, Birgitte; Moreno-Insertis, Fernando; Chandra, Ramesh (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Context. Large-amplitude oscillations (LAOs) are often detected in filaments. Using multi-wavelength observations, their origin can be traced back to the interaction with eruptions and jets. Aims. We present two different ...
  • An interface region imaging spectrograph first view on solar spicules 
    Pereira, Tiago Mendes Domingos; De Pontieu, Bart Walter; Carlsson, Mats; Hansteen, Viggo; Tarbell, T.D.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.; Wulser, J. P.; Martinez-Sykora, Juan; Kleint, L.; Golub, L.; McKillop, S.; Reeves, K. K.; Saar, S.; Testa, Paola; Tian, H; Jaeggli, S.; Kankelborg, C. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere ...
  • Intermittent Reconnection and Plasmoids in UV Bursts in the Low Solar Atmosphere 
    Rouppe van der Voort, Luc; De Pontieu, Bart Walter; Scharmer, G. B.; de la Cruz Rodriguez, Jaime; Martinez-Sykora, Juan; Nobrega-Siverio, Daniel; Guo, L. J.; Jafarzadeh, Shahin; Mendes Domingos Pereira, Tiago; Hansteen, Viggo; Carlsson, Mats; Vissers, Gregal Joan Maria (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Magnetic reconnection is thought to drive a wide variety of dynamic phenomena in the solar atmosphere. Yet, the detailed physical mechanisms driving reconnection are difficult to discern in the remote sensing observations ...
  • Internetwork Chromospheric Bright Grains Observed with IRIS and SST 
    Martinez-Sykora, Juan; Rouppe, Van Der Voort Luc; Carlsson, Mats; De Pontieu, Bart Walter; Mendes Domingos Pereira, Tiago; Boerner, P.; Hurlburt, N.; Kleint, Lucia; Lemen, J.; Tarbell, Ted D.; Title, A.; Wüelser, Jean Pierre; Hansteen, Viggo; Golub, Leon; McKillop, S.; Reeves, K. K.; Saar, S.; Testa, Paola; Tian, Hui; Jaeggli, S.; Kankelborg, C. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    The Interface Region Imaging Spectrograph (IRIS) reveals small-scale rapid brightenings in the form of bright grains all over coronal holes and the quiet Sun. These bright grains are seen with the IRIS 1330, 1400, and 2796 ...
  • The interstellar object ’Oumuamua as a fractal dust aggregate 
    Flekkøy, Eirik Grude; Luu, Jane; Toussaint, Renaud (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The first known interstellar object 'Oumuamua exhibited a nongravitational acceleration that appeared inconsistent with cometary outgassing, leaving radiation pressure as the most likely force. Barring the alien lightsail ...
  • INTRODUCING GAMER: A FAST AND ACCURATE METHOD FOR RAY-TRACING GALAXIES USING PROCEDURAL NOISE 
    Groeneboom, Nicolaas Ervik; Dahle, Håkon (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
    We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components ...
  • The Inverse-C shape of the {\Caiinm} Spectral Line 
    Hole, Ida Benedikte Amlie (Master thesis / Masteroppgave, 2012)
    The inverse-C shape of the bisector from the chromospheric Ca triplet spectral lines is a little understood phenomena. This spectral signature can give valuble information about the chromosphere, which is the least understood ...
  • Investigating 4D coronal heating events in magnetohydrodynamic simulations 
    Kanella, Charalambos; Gudiksen, Boris Vilhelm (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: One candidate model for heating the solar corona is magnetic reconnection that embodies Ohmic dissipation of current sheets. When numerous small-scale magnetic reconnection events occur, then it is possible to ...
  • Investigating coronal wave energy estimates using synthetic non-thermal line widths 
    Fyfe, Lyanne E.; Howson, Thomas A.; de Moortel, Ineke; Pant, Vaibhav; Van Doorsselaere, Tom (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Aims. Estimates of coronal wave energy remain uncertain as a large fraction of the energy is likely hidden in the non-thermal line widths of emission lines. In order to estimate these wave energies, many previous studies ...
  • Investigating cosmological GAN emulators using latent space interpolation 
    Tamosiunas, Andrius; Winther, Hans Arnold; Koyama, Kazuya; Bacon, David; Nichol, Robert C.; Mawdsley, Ben (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    ABSTRACT Generative adversarial networks (GANs) have been recently applied as a novel emulation technique for large-scale structure simulations. Recent results show that GANs can be used as a fast and efficient ...
  • Investigating dynamic small-scale events in the Sun with the Atacama Large Millimeter/sub-millimeter Array 
    Eklund, Henrik (Doctoral thesis / Doktoravhandling, 2021)
    The Sun is dynamic and influences the surrounding planetary system which becomes increasingly imperative to be able to predict as we increase the technology and space exploration. To this end, it is important to understand ...