Browsing Institutt for teoretisk astrofysikk by Title

Now showing items 479-498 of 1279

  • First Spectral Analysis of a Solar Plasma Eruption Using ALMA 
    Rodger, Andrew S.; Labrosse, Nicolas; Wedemeyer, Sven; Szydlarski, Mikolaj Marcin; Simões, Paulo J. A.; Fletcher, Lyndsay (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    The aim of this study is to demonstrate how the logarithmic millimeter continuum gradient observed using the Atacama Large Millimeter/submillimeter Array (ALMA) may be used to estimate optical thickness in the solar ...
  • fkPT: constraining scale-dependent modified gravity with the full-shape galaxy power spectrum 
    Rodriguez-Meza, Mario A.; Aviles, Alejandro; Noriega, Hernan E.; Ruan, Cheng-Zong; Li, Baojiu; Vargas-Magaña, Mariana; Cervantes-Cota, Jorge L. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
    Modified gravity models with scale-dependent linear growth typically exhibit an enhancement in the power spectrum beyond a certain scale. The conventional methods for extracting cosmological information usually involve ...
  • Flare kernels may be smaller than you think: modelling the radiative response of chromospheric plasma adjacent to a solar flare 
    Osborne, Christopher M. J.; Fletcher, Lyndsay (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    ABSTRACT Numerical models of solar flares typically focus on the behaviour of directly heated flare models, adopting magnetic-field-aligned, plane-parallel methodologies. With high spatial- and spectral-resolution ...
  • The forcing and climate response of black carbon aerosols 
    Sand, Maria (Doctoral thesis / Doktoravhandling, 2014)
  • Forecast constraints on anisotropic stress in dark energy using gravitational waves 
    Yang, Weiqiang; Pan, Supriya; Mota, David; Du, Minghui (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    It is always interesting to investigate how well can a future experiment perform with respect to others (present or future ones). Cosmology is really an exciting field where a lot of puzzles are still unknown. In this ...
  • Foreground separation and constraints on primordial gravitational waves with the PICO space mission 
    Aurvik, Ragnhild; Remazeilles, Mathieu; Belkner, Sebastian; Carron, Julien; Delabrouille, Jacques; Eriksen, Hans Kristian Kamfjord; Flauger, Raphael; Fuskeland, Unni; Galloway, Mathew; Górski, Krzysztof M.; Hanany, Shaul; Hensley, Brandon S.; Hill, J. Colin; Lawrence, Charles R.; Pryke, Clement; van Engelen, Alexander; Wehus, Ingunn Kathrine (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    PICO is a concept for a NASA probe-scale mission aiming to detect or constrain the tensor to scalar ratio r, a parameter that quantifies the amplitude of inflationary gravity waves. We carry out map-based component separation ...
  • Formation and heating of chromospheric fibrils in a radiation-MHD simulation 
    Druett, Malcolm K.; Leenarts, Jorrit; Carlsson, Mats; Szydlarski, Mikolaj (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Aims. We examine the movements of mass elements within dense fibrils using passive tracer particles (corks) in order to understand the creation and destruction processes of fibrils. Methods. Simulated fibrils were ...
  • Formation of an observed eruptive flux rope above the torus instability threshold through tether-cutting magnetic reconnection 
    Prasad, Avijeet; Kumar, S.; Sterling, A.C.; Moore, R.L.; Aulanier, Guillaume; Bhattacharyya, R.; Hu, Q. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Context. Erupting magnetic flux ropes (MFRs) are believed to play a crucial role in producing solar flares. However, the formation of erupting MFRs in complex coronal magnetic configurations and the role of their subsequent ...
  • Formation of coronal rain triggered by impulsive heating associated with magnetic reconnection 
    Kohutova, Petra; Verwichte, Erwin; Froment, Clara (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Context. Coronal rain consists of cool plasma condensations formed in coronal loops as a result of thermal instability. The standard models of coronal rain formation assume that the heating is quasi-steady and localised ...
  • Formation of Hϵ in the solar atmosphere 
    Krikova, Kilian; Pereira, Tiago; Rouppe van der Voort, Luc (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Context. In the solar spectrum, the Balmer series line H ε is a weak blend on the wing of Ca  II H. Recent high-resolution H ε spectroheliograms reveal a reversed granulation pattern and in some cases, even unique structures. ...
  • THE FORMATION OF IRIS DIAGNOSTICS. I. A QUINTESSENTIAL MODEL ATOM OF Mg II AND GENERAL FORMATION PROPERTIES OF THE Mg II h&k LINES 
    Leenaarts, Jorrit; Pereira, Tiago Mendes Domingos; Carlsson, Mats; Uitenbroek, H.; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    NASA's Interface Region Imaging Spectrograph (IRIS) space mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager centered ...
  • THE FORMATION OF IRIS DIAGNOSTICS. II. THE FORMATION OF THE Mg II h&k LINES IN THE SOLAR ATMOSPHERE 
    Leenaarts, Jorrit; Pereira, Tiago Mendes Domingos; Carlsson, Mats; Uitenbroek, H.; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h&k lines as well as a slit-jaw imager ...
  • THE FORMATION OF IRIS DIAGNOSTICS. III. NEAR-ULTRAVIOLET SPECTRA AND IMAGES 
    Pereira, Tiago Mendes Domingos; Leenaarts, Jorrit; De Pontieu, Bart Walter; Carlsson, Mats; Uitenbroek, Han (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    The Mg II h&k lines are the prime chromospheric diagnostics of NASA's Interface Region Imaging Spectrograph (IRIS). In the previous papers of this series, we used a realistic three-dimensional radiative magnetohydrodynamics ...
  • THE FORMATION of IRIS DIAGNOSTICS. IV. the Mg ii TRIPLET LINES AS A NEW DIAGNOSTIC FOR LOWER CHROMOSPHERIC HEATING 
    Mendes Domingos Pereira, Tiago; Carlsson, Mats; De Pontieu, Bart Walter; Hansteen, Viggo (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    A triplet of subordinate lines of Mg ii exists in the region around the h&k lines. In solar spectra these lines are seen mostly in absorption, but in some cases can become emission lines. The aim of this work is to study ...
  • The Formation of IRIS Diagnostics. IX. The Formation of the C I 135.58 NM Line in the Solar Atmosphere 
    Lin, Hsiao-Hsuan; Carlsson, Mats; Leenaarts, Jorrit (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    The C i 135.58 nm line is located in the wavelength range of NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission. We study the formation and diagnostic potential of this line by means of non ...
  • THE FORMATION of IRIS DIAGNOSTICS. V. A QUINTESSENTIAL MODEL ATOM of C II and GENERAL FORMATION PROPERTIES of the C II LINES at 133.5 nm 
    Rathore, Bhavna; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    The C ii 133.5nm lines are important observables for the NASA/SMEX mission Interface Region Imaging Spectrograph. To make three-dimensional (3D) non-LTE radiative transfer computationally feasible, it is crucial to have a ...
  • The Formation of IRIS Diagnostics. VI. The Diagnostic Potential of the C II Lines at 133.5 nm in the Solar Atmosphere 
    Rathore, Bhavna; Carlsson, Mats; Leenaarts, Jorrit; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    We use 3D radiation magnetohydrodynamic models to investigate how the thermodynamic quantities in the simulation are encoded in observable quantities, thus exploring the diagnostic potential of the C ii 133.5 nm lines. We ...
  • The Formation of IRIS Diagnostics. VII. The Formation of the O I 135.56 nm Line in the Solar Atmosphere 
    Lin, Hsiao-Hsuan; Carlsson, Mats (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    The O i 135.56 nm line is covered by NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission which studies how the solar atmosphere is energized. We study here the formation and diagnostic potential of ...
  • The Formation of IRIS Diagnostics. VIII. IRIS Observations in the C II 133.5 nm Multiplet 
    Rathore, Bhavna; Mendes Domingos Pereira, Tiago; Carlsson, Mats; De Pontieu, Bart Walter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    The C ii 133.5 nm multiplet has been observed by NASA's Interface Region Imaging Spectrograph (IRIS) in unprecedented spatial resolution. The aims of this work are to characterize these new observations of the C ii lines, ...
  • The formation of small-scale umbral brightenings in sunspot atmospheres 
    Nelson, C. J.; de Jorge Henriques, Vasco Manuel; Mathioudakis, M.; Keenan, F. P. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Context. Sunspot atmospheres have been shown to be highly inhomogeneous hosting both quasi-stable and transient features, such as small-scale umbral brightenings (previously named “umbral micro-jets”) and dark fibril-like ...