Browsing Institutt for teoretisk astrofysikk by Title

Now showing items 655-674 of 1279

  • Low-level Data Analysis, Calibration, and Ground Modeling with COMAP 
    Lunde, Jonas Gahr Sturtzel (Master thesis / Masteroppgave, 2021)
    The CO Mapping Array Project (COMAP) is a line intensity mapping experiment currently in its Pathfinder phase, where it is targeting CO emissions at redshifts z=2.4-3.4. A main goal of the Pathfinder phase is to build a ...
  • Lyman α-emitting galaxies in the epoch of reionization 
    Laursen, Peter; Sommer-Larsen, Jesper; Milvang-Jensen, Bo; Fynbo, Johan P. U.; Razoumov, Alexei O. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    With a total integration time of 168 h and a narrowband filter tuned to Lyα emission from z = 8.8, the UltraVISTA survey has set out to find some of the most distant galaxies, on the verge of the epoch of reionization. ...
  • Lyman-Werner escape fractions from the first galaxies 
    Schauer, Anna T. P.; Agarwal, B.; Glover, Simon C. O.; Klessen, Ralf S.; Latif, Muhammad A.; Mas Ribas, Lluis; Rydberg, Claes-Erik; Whalen, Daniel J.; Zackrisson, Erik (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Direct collapse black holes forming in pristine, atomically cooling haloes at z ≈ 10–20 may act as the seeds of supermassive black holes (BHs) at high redshifts. In order to create a massive BH seed, the host halo needs ...
  • Lyα Profile, Dust, and Prediction of Lyα Escape Fraction in Green Pea Galaxies 
    Yang, Huan; Malhotra, Sangeeta; Gronke, Max Balthasar; Rhoads, James E.; Leitherer, Claus; Wofford, Aida; Jiang, Tianxing; Dijkstra, Mark; Tilvi, V.; Wang, Junxian (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    © 2017. The American Astronomical Society. All rights reserved.
  • The Lyα Reference Sample. VIII. Characterizing Lyα Scattering in Nearby Galaxies 
    Bridge, Joanna S.; Hayes, Matthew; Melinder, Jens; Östlin, Göran; Gronwall, Caryl; Ciardullo, Robin; Atek, Hakim; Cannon, John M.; Gronke, Max Balthasar; Guaita, Lucia; Hagen, Alex; Herenz, Edmund Christian; Kunth, Daniel; Laursen, Peter; Mas-Hesse, J. Miguel; Pardy, Stephen A. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    © 2017. The American Astronomical Society. All rights reserved.
  • The Lyα-LyC connection: evidence for an enhanced contribution of UV-faint galaxies to cosmic reionization 
    Dijkstra, Mark; Gronke, Max Balthasar; Venkatesan, Aparna (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    The escape of ionizing Lyman continuum (LyC) photons requires the existence of low-NH I sightlines, which also promote escape of Lyα. We use a suite of 2500 Lyα Monte-Carlo radiative transfer simulations through models of ...
  • Machine Learning for Searching the Dark Energy Survey for Trans-Neptunian Objects 
    Henghes, Ben; Lahav, Ofer; Gerdes, David W.; Lin, H. W.; Morgan, R.; Abbott, T. M. C.; Aguena, M.; Allam, S.; Annis, J.; Avila, S.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Conselice, C.; Costanzi, M.; Da Costa, L. N.; De Vicente, J.; Desai, S.; Diehl, H. T.; Doel, P.; Everett, S.; Ferrero, Ismael; Frieman, J.; García-Bellido, Juan; Gaztanaga, E.; Gruen, D.; Gruendl, Robert A.; Gschwend, J.; Gutierrez, G.; Hartley, W. G.; Hinton, S. R.; Honscheid, K.; Hoyle, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Marshall, Jennifer L.; Melchior, P.; Menanteau, F.; Miquel, R.; Ogando, R. L. C.; Palmese, Antonella; Paz-Chinchón, Francisco; Plazas, Andrés A.; Romer, A. K.; Sánchez, C.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Serrano, S.; Smith, M.; Soares-Santos, M; Suchyta, E.; Tarle, G.; To, C.; Wilkinson, R. D. (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    In this paper we investigate how implementing machine learning could improve the efficiency of the search for Trans-Neptunian Objects (TNOs) within Dark Energy Survey (DES) data when used alongside orbit fitting. The ...
  • Machine learning initialization to accelerate Stokes profile inversions 
    Gafeira, Ricardo; Orozco Suarez, D.; Milić, Ivan; Quintero Noda, Carlos; Ruiz Cobo, Basilio; Uitenbroek, Han (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Context. At present, an exponential growth in scientific data from current and upcoming solar observatories is expected. Most of the data consist of high spatial and temporal resolution cubes of Stokes profiles taken in ...
  • The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MegaSaura). I. the Sample and the Spectra 
    Rigby, J. R.; Bayliss, M. B.; Sharon, K.; Gladders, M. D.; Chisholm, J.; Dahle, Håkon; Johnson, Traci; Paterno-Mahler, Rachel; Wuyts, E; Kelson, D. D. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    We introduce Project MegaSaura: the Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas. MegaSaura comprises medium-resolution, rest-frame ultraviolet spectroscopy of N = 15 bright gravitationally ...
  • The Magellan Evolution of Galaxies Spectroscopic and Ultraviolet Reference Atlas (MegaSaura). II. Stacked Spectra 
    Rigby, J. R.; Bayliss, M. B.; Chisholm, J.; Bordoloi, Rongmon; Sharon, K.; Gladders, M. D.; Johnson, T.; Paterno-Mahler, Rachel; Wuyts, E; Dahle, Håkon; Acharyya, A. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    We stack the rest-frame ultraviolet spectra of N = 14 highly magnified gravitationally lensed galaxies at redshifts $1.6\lt z\lt 3.6$. The resulting new composite spans $900\lt {\lambda }_{\mathrm{rest}}\lt 3000$ Å, with ...
  • Magnetic characteristics of quiet Sun nanoflares: How to find order out of a tangled mess 
    Robinson, Rebecca A. (Doctoral thesis / Doktoravhandling, 2023)
    Nanoflares are tiny, energetic explosions on the Sun—and we accidentally simulated one. This work focuses on the development and characteristics of a nanoflare-scale magnetic reconnection event that was simulated using our ...
  • Magnetic field variations associated with umbral flashes and penumbral waves 
    Joshi, Jayant; de la Cruz Rodriguez, Jaime (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Context: Umbral flashes (UF) and running penumbral waves (RPWs) in sunspot chromospheres leave a dramatic imprint in the intensity profile of the Ca II 8542 Å line. Recent studies have focussed on also explaining the ...
  • Magnetic field-aligned plasma currents in gravitational fields 
    Garcia, Odd Erik; Leer, Egil; Pecseli, Hans; Trulsen, Jan Karsten (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    Analytical models are presented for currents along vertical magnetic field lines due to slow bulk electron motion in plasmas subject to a gravitational force. It is demonstrated that a general feature of this problem is a ...
  • Magnetic imaging of the outer solar atmosphere (MImOSA): Unlocking the driver of the dynamics in the upper solar atmosphere 
    Peter, Hardi; Ballester, Ernest Alsina; Andretta, Vincenzo; Auchère, Frédéric; Belluzzi, Luca; Bemporad, Alberto; Berghmans, D.; Buchlin, Éric; Calcines, Ariadna; Chitta, Lakshmi Pradeep; Dalmasse, K.; del Pino Alemán, Tanausú; Feller, A.; Froment, Clara; Harrison, R.; Janvier, M.; Matthews, S.; Parenti, S.; Przybylski, D.; Solanki, Sami K.; Štěpán, Jiří; Teriaca, L.; Trujillo Bueno, Javier (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Abstract The magnetic activity of the Sun directly impacts the Earth and human life. Likewise, other stars will have an impact on the habitability of planets orbiting these host stars. Although the magnetic field at the ...
  • Magnetic reconnection and the Kelvin-Helmholtz instability in the solar corona 
    Howson, Thomas A.; De Moortel, Moortel; Pontin, David I. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Context. The magnetic Kelvin-Helmholtz instability (KHI) has been proposed as a means of generating magnetohydrodynamic turbulence and encouraging wave energy dissipation in the solar corona, particularly within transversely ...
  • MAGNETIC UPFLOW EVENTS IN THE QUIET-SUN PHOTOSPHERE. I. OBSERVATIONS 
    Jafarzadeh, Shahin; Rouppe, Van Der Voort Luc; de la Cruz Rodriguez, Jaime (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
    Rapid magnetic up fl ows in the quiet-Sun photosphere were recently uncovered from both SUNRISE / IMaX and Hinode / SOT observations. Here, we study magnetic up flow events ( MUEs ) from high-quality, high- ( spatial, ...
  • Magnetically charged black holes from non-linear electrodynamics and the Event Horizon Telescope 
    Allahyari, Alireza; Khodali, Mohsen; Vagnozzi, Sunny; Mota, David (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    Non-linear electrodynamics (NLED) theories are well-motivated extensions of QED in the strong field regime, and have long been studied in the search for regular black hole (BH) solutions. We consider two well-studied and ...
  • Magnetoacoustic wave energy dissipation in the atmosphere of solar pores 
    Gilchrist-Millar, Caitlin A.; Jess, David B.; Grant, Samuel D. T.; Keys, Peter H.; Beck, Christian; Jafarzadeh, Shahin; Riedl, Julia M.; Van Doorsselaere, Tom; Ruiz Cobo, Basilio (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2020)
    The suitability of solar pores as magnetic wave guides has been a key topic of discussion in recent years. Here, we present observational evidence of propagating magnetohydrodynamic wave activity in a group of five ...
  • Magnetohydrodynamic Nonlinearities in Sunspot Atmospheres: Chromospheric Detections of Intermediate Shocks 
    Houston, Scott J.; Jess, David B.; Keppens, Rony; Stangalini, Marco; Keys, Peter H.; Grant, Samuel D. T.; Jafarzadeh, Shahin; McFetridge, L. M.; Murabito, Mariarita; Ermolli, I.; Giorgi, F. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
  • Magnetohydrodynamic waves in braided magnetic fields 
    Howson, T. A.; de Moortel, Ineke; Reid, J.; Hood, A. W. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Aims. We investigate the propagation of transverse magnetohydrodynamic (MHD) wave fronts through a coronal plasma containing a braided magnetic field. Methods. We performed a series of three dimensional MHD simulations ...