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Now showing items 201-300 of 1297
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We present SymPix, a special-purpose spherical grid optimized for efficiently sampling rotationally invariant linear operators. This grid is conceptually similar to the Gauss–Legendre (GL) grid, aligning sample points with ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We analyze observations from the Interface Region Imaging Spectrograph of the Mg ii k line, the Mg ii UV subordinate lines, and the O i 135.6 $\mathrm{nm}$ line to better understand the solar plage chromosphere. We also ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
The Ca II 854.2 nm spectral line is a common diagnostic of the solar chromosphere. The average line profile shows an asymmetric core, and its bisector shows a characteristic inverse-C shape. The line actually consists of ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
Recently, a supersymmetric model of dark energy coupled to cold dark matter, the supersymmetron, has been proposed. In the absence of cold dark matter, the supersymmetron field converges to a supersymmetric minimum with a ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
We present a new flexible Bayesian framework for directly inferring the fraction of neutral hydrogen in the intergalactic medium (IGM) during the Epoch of Reionization (EoR, z ~ 6–10) from detections and non-detections of ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
In this paper, we present the first results from implementing two scalar–tensor modified gravity theories, the symmetron and the Hu–Sawicki f(R)-gravity model, into a hydrodynamic N-body code with dark matter particles and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
The measurement of the large-scale B-mode polarization in the cosmic microwave background (CMB) is a fundamental goal of future CMB experiments. However, because of unprecedented sensitivity, future CMB experiments will ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Advanced three-dimensional (3D) radiative MHD simulations now reproduce many properties of the outer solar atmosphere. When including a domain from the convection zone into the corona, a hot chromosphere and corona are ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2011)
We introduce the N-body simulation technique to follow structure formation in linear and nonlinear regimes for the extended quintessence models (scalar-tensor theories in which the scalar field has a self-interaction ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
It is shown that a disformally coupled theory in which the gravitational sector has the Einstein-Hilbert form is equivalent to a quartic Dirac-Born-Infeld Galileon Lagrangian, possessing nonlinear higher derivative ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
Cosmological local observables are at best statistically determined by the fundamental theory describing inflation. When the scalar inflaton is coupled uniformly to a collection of subdominant massless gauge vectors, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Penumbral microjets (PMJs) are short-lived, fine-structured, and bright jets that are generally observed in chromospheric imaging of the penumbra of sunspots. Here we investigate their potential transition region signature ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present a unified computational framework that can be used to describe impulsive flares on the Sun and on dMe stars. The models assume that the flare impulsive phase is caused by a beam of charged particles that is ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Aims: We study the effects of letting dark matter and gas in the Universe couple to the scalar field of the symmetron model, a modified gravity theory, with varying coupling strength. We also search for a way to distinguish ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
In recent years realistic 3D numerical models of the solar atmosphere have become available. The models attempt to recreate the solar atmosphere and mimic observations in the best way, in order to make it possible to couple ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We propose an efficient Bayesian Markov chain Monte Carlo (MCMC) algorithm for estimating cosmological parameters from cosmic microwave background (CMB) data without the use of likelihood approximations. It builds on a ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
The properties of nonstatistical equilibrium ionization of silicon and oxygen ions are analyzed in this work. We focus on five solar targets (quiet Sun; coronal hole; plage; quiescent active region, AR; and flaring AR) as ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Solar flares involve complex processes that are coupled and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present results ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in UV spectral lines. Here we apply PORTA ( a novel radiative ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
We revisit the question of hemispherical power asymmetry in the WMAP and Planck temperature sky maps by measuring the local variance over the sky and on disks of various sizes. For the 2013 Planck sky map we find that none ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present a mass estimate of the Planck-discovered cluster PLCK G100.2-30.4, derived from a weak lensing analysis of deep Subaru griz images. We perform a careful selection of the background galaxies using the multi-band ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
There is a thin transition region (TR) in the solar atmosphere where the temperature rises from 10,000 K in the chromosphere to millions of degrees in the corona. Little is known about the mechanisms that dominate this ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We describe a new quiet-Sun phenomenon which we call quiet-Sun Ellerman-like brightenings (QSEB). QSEBs are similar to Ellerman bombs (EB) in some respects but differ significantly in others. EBs are transient brightenings ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
As part of an all-sky follow-up of the Planck catalogue of Sunyaev-Zeldovich (SZ) cluster candidates detected in the first 14 months of data, we are observing cluster candidates in the southern sky in the optical imaging ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα line. We study the origin, dynamics, and thermal properties of the jets using high-resolution ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present polarization observations of two Galactic plane fields centered on Galactic coordinates (l, b) = (0°, 0°) and (329°, 0°) at both Q (43 GHz) and W bands (95 GHz), covering between 301 and 539 square degrees ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
In the context of scalar tensor theories for gravity, there is a universally adopted hypothesis when running N-body simulations that time derivatives in the equation of motion for the scalar field are negligible. In this ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Screened modified gravity predicts potentially large signatures in the peculiar velocity field that makes it an interesting probe to test gravity on cosmological scales. We investigate the signatures induced by the Symmetron ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Spectroscopic observations of prominence eruptions associated with coronal mass ejections (CMEs), although relatively rare, can provide valuable plasma and three-dimensional geometry diagnostics. We report the first ...
(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, 2015)
The Mg ii h&k doublet are two of the primary spectral lines observed by the Sun-pointing Interface Region Imaging Spectrograph (IRIS). These lines are tracers of the magnetic and thermal environment that spans from the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We test for foreground residuals in the foreground-cleaned Planck cosmic microwave background (CMB) maps outside and inside the U73 mask commonly used for cosmological analysis. The aim of this paper is to introduce a new ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Magnetic flux emergence into the outer layers of the Sun is a fundamental mechanism for releasing energy into the chromosphere and the corona. In this paper, we study the emergence of granular-sized flux concentrations and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Ellerman bombs are transient brightenings of the wings of the solar Balmer lines that mark reconnection in the photosphere. Ellerman noted in 1917 that he did not observe such brightenings in the Na i D and Mg i b lines. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
High resolution observations from the Swedish 1-m Solar Telescope revealed bright, discrete, blob-like structures (which we refer to as solar bullets) in the Hα 656.28 nm line core that appear to propagate laterally across ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We report fi rst results from an ongoing monitoring campaign to measure time delays between the six images of the quasar SDSS J2222 + 2745, gravitationally lensed by a galaxy cluster. The time delay between A and B, the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We use coordinated observations with the Interface Region Imaging Spectrograph (IRIS) and the Swedish 1 m Solar Telescope to identify the disk counterpart of type II spicules in upper-chromospheric and transition region ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Transverse magnetohydrodynamic waves have been shown to be ubiquitous in the solar atmosphere and can, in principle, carry sufficient energy to generate and maintain the Sun's million-degree outer atmosphere or corona. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present Chandra and XMM-Newton observations of PLCK G036.7+14.9 from the Chandra–Planck Legacy Program. The high resolution X-ray observations reveal two close (~72'' = 193 kpc in projection) subclusters, G036N and ...
(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, 2015)
We present observations and analysis of a sample of 123 galaxy clusters from the 2013 Planck catalogue of Sunyaev-Zel’dovich sources with the Arcminute Microkelvin Imager (AMI), a ground-based radio interferometer. AMI ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
Scalar fields, strongly coupled to matter, can be present in nature and still be invisible to local experiments if they are subject to a screening mechanism. The symmetron is one such mechanism that relies on restoration ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Context: The reionisation of the Universe is a process that is thought to have ended around z ~ 6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst (GRB) afterglows. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
Recent detections of Lyman alpha (Lyα) emission from z > 7.5 galaxies were somewhat unexpected given a dearth of previous non-detections in this era when the intergalactic medium (IGM) is still highly neutral. But these ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
Scalar fields are crucial components in high energy physics and extensions of general relativity. The fact that they are not observed in the Solar System may be due to a mechanism which screens their presence in high dense ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
Cosmological perturbations due to statistical thermal fluctuations in a single fluid characterized by an arbitrary equation of state are computed. Formulas to predict the scalar and tensor perturbation spectra and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
We present the most general covariant ghost-free gravitational action in a Minkowski vacuum. Apart from the much studied f(R) models, this includes a large class of nonlocal actions with improved UV behavior, which ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We report on observations of recurrent jets by instruments on board the Interface Region Imaging Spectrograph, Solar Dynamics Observatory (SDO), and Hinode spacecraft. Over a 4 hr period on 2013 July 21, recurrent coronal ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Ellerman bombs (EBs) are transient brightenings of the extended wings of the solar Balmer lines in emerging active regions. We describe their properties in the ultraviolet lines sampled by the Interface Region Imaging ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Spicules are ubiquitous, fast moving jets observed off-limb in chromospheric spectral lines. Combining the recently launched Interface Region Imaging Spectrograph with the Solar Dynamics Observatory and Hinode, we have a ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Observations of the solar chromosphere in the line core of the Hα line show dark elongated structures called fibrils that show swaying motion. We performed a three-dimensional radiation-MHD simulation of a network region ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
Recently, a modified theory of gravity was presented, which consists of the superposition of the metric Einstein-Hilbert Lagrangian with an f(R) term constructed à la Palatini. The theory possesses extremely interesting ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
In the first-order formalism of gravitational theories, the spacetime connection is considered as an independent variable to vary together with the metric. However, the metric still generates its Levi-Civita connection ...
(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 ...
(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, ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We analyze coordinated observations of coronal rain in loops, spanning chromospheric, transition region (TR), and coronal temperatures with sub-arcsecond spatial resolution. Coronal rain is found to be a highly multithermal ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
We present a comprehensive method to analyze small-scale heating events in detail in a 3D magnetohydrodynamics simulation for quiet-Sun conditions. The method determines the number, volume, and some general geometric ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
The bimetric variational principle is a subtle reinterpretation of general relativity that assumes the spacetime connection to be generated by an independent metric. Unlike the so-called Palatini formalism that promotes ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
New Hubble Space Telescope ultraviolet and optical imaging of the strong-lensing galaxy cluster SDSS J1531+3414 (z = 0.335) reveals two centrally dominant elliptical galaxies participating in an ongoing major merger. The ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2015)
Modified gravity models require a screening mechanism to be able to evade the stringent constraints from local gravity experiments and, at the same time, give rise to observable astrophysical and cosmological signatures. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We study, for the first time, the ascent of granular-sized magnetic bubbles from the solar photosphere through the chromosphere into the transition region and above. Such events occurred in a flux emerging region in NOAA ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
We consider modified gravity models driven by a scalar field whose effects are screened in high density regions due to the presence of nonlinearities in its interaction potential and/or its coupling to matter. Our approach ...
(Master thesis / Masteroppgave, 2017)
Following the discovery of the late-time acceleration, a multitude of extensions to General Relativity have been developed, seeking to shed light on this new phenomenon. Some of these models involve couplings to ordinary ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2020)
The present studies address feeding of plankton in turbulent environments, discussed by a comparison of analytical results and field data. Various models for predator-prey encounters and capture probabilities are reviewed. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
This paper describes the methods used to produce photometrically calibrated maps from the Planck High Frequency Instrument (HFI) cleaned, time-ordered information. HFI observes the sky over a broad range of frequencies, ...
(Master thesis / Masteroppgave, 2017)
The Next Generation Transit Survey (NGTS) is an ongoing wide-field exoplanet transit survey at ESO Paranal Observatory, Chile. It is searching for Neptune and super-Earth size planets around nearby stars using 12 robotic ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
We investigate the variation of the fine-structure constant, α, in symmetron models using N-body simulations in which the full spatial distribution of α at different redshifts has been calculated. In particular, we obtain ...
(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. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
With reference to laboratory Q-machine studies we analyze the dynamics of a plasma diode under external forcing. Assuming a strong axial magnetic field, the problem is analyzed in one spatial dimension by a particle-in-cell ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
Several extensions of general relativity and high energy physics include scalar fields as extra degrees of freedom. In the search for predictions in the nonlinear regime of cosmological evolution, the community makes use ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
We study properties of domain walls in the symmetron model, in which the scalar gravitational degree of freedom decouples from matter in regions of high density and exhibits a spontaneously broken Z2 symmetry at low ...
(Master thesis / Masteroppgave, 2016)
Several decades ago it was discovered that the outer layers of the Sun are much hotter than the photosphere. The mechanism or mechanisms heating the outer solar layers are not known, so this is known as the coronal heating ...
(Master thesis / Masteroppgave, 2016)
Recent observations support a significantly reduced visibility of Lyman-α (Lyα) flux from galaxies at redshifts z > 6. This is surprising considering that the visibility of Lyα flux has been observed to increase up towards ...
(Doctoral thesis / Doktoravhandling, 2007)
Doktorgradsavhandlingen beskriver et programvarebibliotek utviklet av Øystein Olsen ved Institutt for teoretisk astrofysikk.
Programvaren har blitt brukt til å finne regioner med stabile og ustabile baner rundt asteroider ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
Reproduced with permission from Astronomy & Astrophysics, © ESO, 2016
(Master thesis / Masteroppgave, 2016)
(Master thesis / Masteroppgave, 2013)
Modified gravity theories are a popular research field in the hope that they could explain some of the unanswered questions in cosmology, for example how the universe starts, evolves and ends. One way to test proposed ...
(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 ...
(Master thesis / Masteroppgave, 2019)
I calculate Lyman-α luminosity and surface brightness; and find that the values are much higher than typical for this kind of galaxy. I find this is due to very high star formation rate; which makes the galaxy superluminous.
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
We characterize the K i D1 & D2 lines in order to determine whether they could complement the 850 nm window, containing the Ca ii infrared triplet lines and several Zeeman sensitive photospheric lines, that was studied ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
We perform non-LTE inversions in a large set of umbral flashes, including the dark fibrils visible within them, and in the quiescent umbra by using the inversion code NICOLE on a set of full Stokes high-resolution Ca ii ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
A massive and luminous perturber moving across an opaque gas is subjected to a force different from the gravitational friction that it would experience if it were cold. The heat released by the perturber diffuses in the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2014)
We study a granular-sized magnetic flux emergence event that occurred in NOAA 11024 in 2009 July. The observations were made with the CRISP spectropolarimeter at the Swedish 1 m Solar Telescope achieving a spatial resolution ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H i Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
Context. The solar chromosphere is the interface between the solar surface and the solar corona. Modelling of this region is difficult because it represents the transition from optically thick to thin radiation escape, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2013)
Observations in the Hα line of hydrogen and the H and K lines of singly ionized calcium on the solar limb reveal the existence of structures with jet-like behavior, usually designated as spicules. The driving mechanism for ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest ...