Browsing Institutt for teoretisk astrofysikk by Title

Now showing items 1019-1038 of 1279

  • Revealing the Warm and Hot Halo Baryons via Thomson Scattering of Quasar Light 
    Mas Ribas, Lluis; Hennawi, Joseph F (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    The baryonic content and physical properties of the warm and hot (105 lesssim T lesssim 107 K) phases of the circumgalactic medium (CGM) are poorly constrained owing to the lack of observables probing the requisite range ...
  • Revisiting Vainshtein screening for fast N-body simulations 
    Brando, Guilherme; Koyama, Kazuya; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    We revisit a method to incorporate the Vainshtein screening mechanism in N-body simulations proposed by R. Scoccimarro in [1]. We further extend this method to cover a subset of Horndeski theories that evade the bound on ...
  • RH 1.5D: A massively parallel code for multi-level radiative transfer with partial frequency redistribution and Zeeman polarisation 
    Mendes Domingos Pereira, Tiago; Uitenbroek, Han (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    The emergence of three-dimensional magneto-hydrodynamic simulations of stellar atmospheres has sparked a need for efficient radiative transfer codes to calculate detailed synthetic spectra. We present RH 1.5D, a massively ...
  • Robust diffraction-limited near-infrared-to-near-ultraviolet wide-field imaging from stratospheric balloon-borne platforms—Super-pressure Balloon-borne Imaging Telescope performance 
    Romualdez, L. Javier; Benton, Steven J.; Brown, Anthony M.; Clark, Paul; Damaren, Christopher J.; Eifler, Tim; Fraisse, Aurélien A.; Galloway, Mathew; Gill, Ajay; Hartley, John W.; Holder, Bradley; Huff, Eric M.; Jauzac, Mathilde; Jones, William C.; Lagattuta, David; Leung, Jason S.-Y.; Li, Lun; Luu, Thuy Vy T.; Massey, Richard J.; McCleary, Jacqueline; Mullaney, James; Nagy, Johanna M.; Netterfield, Calvin Barth; Redmond, Susan; Rhodes, Jason D.; Schmoll, Jürgen; Shaaban, Mohamed M.; Sirks, Ellen; Tam, Sut-Ieng (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    At a fraction of the total cost of an equivalent orbital mission, scientific balloon-borne platforms, operating above 99.7% of the Earth’s atmosphere, offer attractive, competitive, and effective observational capabilities—namely, ...
  • Robust sampling for weak lensing and clustering analyses with the Dark Energy Survey 
    Lemos, Pablo; Weaverdyck, Noah; Rollins, Richard P.; Muir, J.; Ferté, Agnès; Liddle, A. R.; Campos, A.; Huterer, Dragan; Raveri, Marco; Zuntz, Joseph; Di Valentino, Eleonora; Fang, X.; Hartley, William G.; Aguena, Michel; Allam, Sahar; Annis, J.; Bertin, Emmanuel; Bocquet, S.; Brooks, D.; Burke, David L.; Cornero Rosell, Aurelio; Carrasco Kind, Matias; Carretero, J.; Castander, Francisco Javier; Choi, A.; Costanzi, M.; Crocce, M.; da Costa, Luiz N.; Pereira, Maria Elidaiana da Silva; Dietrich, J. P.; Everett, S.; Ferrero, Ismael; Frieman, Joshua A.; García-Bellido, Juan; Gatti, M.; Gaztañaga, Enrique; Gerdes, David W.; Gruen, D.; Gruendl, Robert A.; Gschwend, J.; Gutierrez, G.; Hinton, Samuel R.; Hollowood, Devon L.; Honscheid, K.; James, David J.; Kuehn, Kyler; Kuropatkin, Nikolay; Lima, M.; March, M.; Melchior, P.; Menanteau, Felipe; Miquel, R.; Morgan, R.; Palmese, A.; Paz-Chinchón, Francisco; Pieres, A.; Plazas Malagón, Andrés A.; Porredon, A.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, Ignacio; Smith, Mathew; Suchyta, E.; Swanson, Molly E. C.; Tarlé, Gregory; Thomas, D.; To, Chun-Hao; Varga, Tamas Norbert; Weller, Jochen (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    ABSTRACT Recent cosmological analyses rely on the ability to accurately sample from high-dimensional posterior distributions. A variety of algorithms have been applied in the field, but justification of the ...
  • The role of resistivity in plasmoid-mediated reconnection in the solar corona and its observational imprints 
    Færder, Øystein Håvard (Doctoral thesis / Doktoravhandling, 2024)
    Magnetic reconnection is a fundamental mechanism in astrophysics and a promising candidate for solving the coronal heating problem. This process has been shown to produce a variety of different observable phenomena on the ...
  • Scalar perturbations in f(T) gravity using the 1+3 covariant approach 
    Sahlu, Shambel; Ntahompagaze, Joseph; Abebe, Amare; de la Cruz Dombriz, Álvaro; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
  • SCALAR: an AMR code to simulate axion-like dark matter models 
    Mina, Mattia; Mota, David; Winther, Hans Arnold (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    We present a new code,SCALAR, based on the high-resolution hydrodynamics andN-body codeRAMSES, to solve the Schrödingerequation on adaptive refined meshes. The code is intended to be used to simulate axion ...
  • Screening mechanisms in hybrid metric-Palatini gravity 
    Vargas dos santos, Marcelo; Alcaniz, Jailson S; Mota, David; Capozziello, Salvatore (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    We investigate the efficiency of screening mechanisms in the hybrid metric-Palatini gravity. The value of the field is computed around spherical bodies embedded in a background of constant density. We find a thin shell ...
  • Screening Modifications of Gravity Through Disformally Coupled Fields 
    Koivisto, Tomi Sebastian; Mota, David; Zumalacárregui, Miguel (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    It is shown that extensions to general relativity, which introduce a strongly coupled scalar field, can be viable if the interaction has a nonconformal form. Such disformal coupling depends upon the gradients of the scalar ...
  • Screenings in modified gravity: a perturbative approach 
    Aviles, Alejandro; Cervantes-Cota, Jorge L; Mota, David (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    We present a formalism to study screening mechanisms in modified theories of gravity through perturbative methods in different cosmological scenarios. We consider Einstein-frame posed theories that are recast as Jordan-frame ...
  • SDSS J2222+2745: A GRAVITATIONALLY LENSED SEXTUPLE QUASAR WITH A MAXIMUM IMAGE SEPARATION OF 15."1 DISCOVERED IN THE SLOAN GIANT ARCS SURVEY 
    Dahle, Håkon; Gladders, M. D.; Sharon, K.; Bayliss, M. B.; Wuyts, E; Abramson, L. E.; Koester, B. P.; Groeneboom, Nicolaas Ervik; Brinckmann, T. E.; Kristensen, M. T.; Lindholmer, M. O.; Nielsen, A; Krogager, J.-K.; Fynbo, J.P.U. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    We report the discovery of a unique gravitational lens system, SDSS J2222+2745, producing five spectroscopically confirmed images of a zs = 2.82 quasar lensed by a foreground galaxy cluster at zl = 0.49. We also present ...
  • The SDSS-DR12 large-scale cross-correlation of damped Lyman alpha systems with the Lyman alpha forest 
    Pérez-Ràfols, Ignasi; Font-Ribera, Andreu; Miralda-Escudé, Jordi; Blomqvist, Michael; Bird, Simeon; Busca, Nicolás G.; du Mas des Bourboux, Hélion; Mas Ribas, Lluis; Noterdaeme, Pasquier; Petitjean, Patrick; Rich, James; Schneider, Donald P. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
  • The search for inflationary B-mode signal with future CMB experiments 
    Aurvik, Ragnhild (Doctoral thesis / Doktoravhandling, 2023)
    The oldest radiation in the universe is the Cosmic Microwave Background (CMB) radiation. Analysing the CMB is like analysing a baby picture of the Universe, and gives us unique information on what the Universe looked like ...
  • Searching for anomalies in the cosmic microwave background 
    Groeneboom, Nicolaas Ervik (Doctoral thesis / Doktoravhandling, 2010)
  • Searching for B-modes with QUIET: A reanalysis of the first-season Q-band data 
    Ruud, Tone Melvær (Master thesis / Masteroppgave, 2012)
    The Q/U-Imaging ExperimenT (QUIET) is a ground-based coherent polarimeter experiment, primarily targeting the detection of low-l B-mode polarization in the CMB. Such modes are a signature of primordial tensor perturbations, ...
  • Searching for stellar emission in the sub-THz bands 
    Kirkaune, Mats (Master thesis / Masteroppgave, 2023)
  • Self-consistent 3D radiative magnetohydrodynamic simulations of coronal rain formation and evolution 
    Kohutova, Petra; Antolin, Patrick; Popovas, Andrius; Szydlarski, Mikolaj Marcin; Hansteen, Viggo (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
    Context. Coronal rain consists of cool and dense plasma condensations formed in coronal loops as a result of thermal instability. Aims. Previous numerical simulations of thermal instability and coronal rain formation have ...
  • Self-similar space-time evolution of an initial density discontinuity 
    Rekaa, Vegard Lundby; Pecseli, Hans; Trulsen, Jan Karsten (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
    The space-time evolution of an initial step-like plasma density variation is studied. We give particular attention to formulate the problem in a way that opens for the possibility of realizing the conditions experimentally. ...
  • Semi-empirical model atmospheres for the chromosphere of the sunspot penumbra and umbral flashes 
    Bose, Souvik; de Jorge Henriques, Vasco Manuel; Rouppe van der Voort, Luc; Mendes Domingos Pereira, Tiago (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Context: The solar chromosphere and the lower transition region are believed to play a crucial role in the heating of the solar corona. Models that describe the chromosphere (and the lower transition region), accounting ...