Now showing items 257-276 of 593

• (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 ...
• (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 ...
• (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 ...
• (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 ...
• (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, ...
• (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 ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
We derive the mass-temperature relation using an improved top-hat model and a continuous formation model which takes into account the effects of the ordered angular momentum acquired through tidal-torque interaction between ...
• (Master thesis / Masteroppgave, 2008)
• (Master thesis / Masteroppgave, 2010)
Neutrino cosmology is a very interesting field of research, where properties of some of the smallest constituents of the universe are probed by the very largest structures of the universe; large scale structures of the ...
• (Master thesis / Masteroppgave, 2016)
Spherical collapse is a crude, but useful toy model for structure formation in an expanding universe. Previous works have looked at this model in ΛCDM with massive neutrinos, where the primary findings were that massive ...
• (Doctoral thesis / Doktoravhandling, 2012)
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
We study the mean absorption spectrum of the Damped Lyα (DLA) population at z ~ 2.6 by stacking normalized, rest-frame-shifted spectra of ~27,000 DLA systems from the DR12 of the Baryon Oscillation Spectroscopic Survey ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
We present a measurement of the cosmic microwave background lensing potential using 500 deg2 of 150 GHz data from the SPTpol receiver on the South Pole Telescope. The lensing potential is reconstructed with signal-to-noise ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
The bias factor of damped Ly α (DLAs) systems, derived from the cross-correlation with the Ly α forest in absorption spectra of the Baryon Oscillation Spectroscopic Survey of SDSS-III, has been used to infer the characteristic ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
We present a novel approach to modified theories of gravity which consists of adding to the Einstein-Hilbert Lagrangian an f(R) term constructed à la Palatini. Using the respective dynamically equivalent scalar-tensor ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar corona where the highly structured magnetic fields provide efficient wave guides for their propagation. While MHD waves have been observed originating ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Context. Penumbral microjets (PMJs) are short-lived jets found in the penumbra of sunspots, first observed in wide-band Ca ii H line observations as localized brightenings, and are thought to be caused by magnetic reconnection. ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Aims: We use advanced 3D non-local thermodynamic equilibrium radiative magnetohydrodynamic simulations of the solar atmosphere to carry out detailed tests of chromospheric diagnostics at millimeter and submillimeter ...
• (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
Aims. We use state-of-the-art, three-dimensional non-local thermodynamic equilibrium (non-LTE) radiative magnetohydrodynamic simulations of the quiet solar atmosphere to carry out detailed tests of chromospheric magnetic ...