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Now showing items 1201-1300 of 1306
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
We present asevolution, a cosmological N-body code developed based on gevolution, which consistently solves for the (a)symmetron scalar field and metric potentials within the weak-field approximation. In asevolution, the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
The existence of multiple active galactic nuclei (AGNs) at small projected distances on the sky is due to either the presence of multiple, inspiraling supermassive black holes, or to gravitational lensing of a single AGN. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. Fabry–Pérot interferometers (FPIs) have become very popular in solar observations because they offer a balance between cadence, spatial resolution, and spectral resolution through a careful design of the spectral ...
(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. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract To recognize gravitational wave lensing events and being able to differentiate between similar lens models will be of crucial importance once one will be observing several lensing events of gravitational waves per ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
ABSTRACT
Recent cosmological analyses with large-scale structure and weak lensing measurements, usually referred to as 3 × 2pt, had to discard a lot of signal to noise from small scales due to our inability to ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
In this paper, we study the effective field theory (EFT) of dark energy (DE) for the k-essence model beyond linear order. Using particle-mesh N-body simulations that consistently solve the DE evolution on a grid, we find ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Recent cosmic shear studies have shown that higher-order statistics (HOS) developed by independent teams now outperform standard two-point estimators in terms of statistical precision thanks to their sensitivity to the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilize the extensive suite of remote-sensing and in situ instruments on board the ESA/NASA Solar Orbiter ...
(Doctoral thesis / Doktoravhandling, 2024)
In my thesis, I investigated local (ultra-)luminous infrared galaxies, typically identified as galaxy mergers. These galaxies are fascinating due to their intense star formation and active galactic nuclei, which can lead ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
We present the first Bayesian method for tomographic decomposition of the plane-of-sky orientation of the magnetic field with the use of stellar polarimetry and distance. This standalone tomographic inversion method presents ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. The H α line, one of the most studied chromospheric diagnostics, is a tracer of magnetic field structures, while the intensity of its line core provides an estimate of the mass density. The interpretation of H α ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
Coronal bright points (CBPs) are sets of small-scale coronal loops, connecting opposite magnetic polarities, primarily characterized by their enhanced extreme-ultraviolet (EUV) and X-ray emission. Being ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context . Three-dimensional non-local thermodynamical equilibrium (NLTE) radiative transfer calculations are a fundamental tool for a detailed spectral analysis in stellar atmospheres, but require vast amounts of computer ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
The Mg ii h and k lines are among the best diagnostic tools of the upper solar chromosphere. This region of the atmosphere is of particular interest, as it is the lowest region of the Sun's atmosphere where the magnetic ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. Magnetic reconnection is a fundamental mechanism in astrophysics. A common challenge in mimicking this process numerically in particular for the Sun is that the solar electrical resistivity is small compared to ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. In November 2021, Solar Orbiter started its nominal mission phase. The remote-sensing instruments on board the spacecraft acquired scientific data during three observing windows surrounding the perihelion of the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
Nanoflares are regarded as one of the major mechanisms of magnetic energy release and coronal heating in the solar outer atmosphere. We conduct a statistical study on the response of the chromosphere and ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
Observations by the Interface Region Imaging Spectrograph (IRIS) of the Mg ii h & k spectral lines have provided a new diagnostic window toward knowledge of the complex physical conditions in the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
Understanding the mechanisms underlying the heating of the solar atmosphere is a fundamental problem in solar physics. In this paper, we present an overview of our research on understanding the heating ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
The dynamic atmosphere imposes challenges to ground-based cosmic microwave background observation, especially for measurements on large angular scales. The hydrometeors in the atmosphere, mostly in the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. Next-generation wide-field optical polarimeters such as Wide-Area Linear Optical Polarimeters (WALOPs) have a field of view (FoV) of tens of arcminutes. Wide-field polarimetric flat sources are essential to the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
We report on the disk-averaged absolute brightness temperatures of Venus measured at four microwave frequency bands with the Cosmology Large Angular Scale Surveyor. We measure temperatures of 432.3 ± ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. The non-Gaussian Cold Spot surrounded by its hot ring is one of the most striking features of the cosmic microwave background (CMB) and has generated significant attention in the literature. It has been speculated ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Chapter / Bokkapittel / PublishedVersion; Peer reviewed, 2023)
The Lambda-Cold Dark Matter (ΛCDM) model agrees with most of the cosmological observations, but has some hindrances from observed data at smaller scales such as galaxies. Recently, Berezhiani and Khoury proposed a new ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
The Gaia Multipeak (GMP) technique can be used to identify large numbers of dual or lensed active galactic nucleus (AGN) candidates at subarcsec separation, allowing us to study both multiple supermassive black holes (SMBHs) ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Particle acceleration is a fundamental process arising in many astrophysical objects, including active galactic nuclei, black holes, neutron stars, gamma-ray bursts, accretion disks, solar and stellar coronae, and planetary ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
We present a detailed chemical abundance analysis of the brightest star in the ultrafaint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra. For this star, DES J011740.53-173053, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
We conduct a systematic search for transients in 3 yr of data (2017–2019) from the Atacama Cosmology Telescope (ACT). ACT covers 40% of the sky at three bands spanning from 77–277 GHz. Analysis of 3 day ...
(Doctoral thesis / Doktoravhandling, 2023)
The Sun, our nearest star, serves as an invaluable reference for the study of solar-like stars, due to the availability of many spatiotemporally resolved solar spectra. Amongst several spectral lines, some of the strongest ...
(Chapter / Bokkapittel / PublishedVersion; Peer reviewed, 2023)
The Atacama Large Aperture Submillimeter Telescope (At- LAST) aims to be the premier next generation large diameter (50 meter) single dish observatory capable of observations across the millimeter/submillimeter spectrum, ...
(Doctoral thesis / Doktoravhandling, 2023)
Massive neutrinos and alternative theories of gravity are two seemingly different aspects of cosmological study. On one hand, we have actual particles known to exist, and on the other, a proposed change to the description ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
The O i 1355 Å spectral line is one of the only optically thin lines that are both routinely observed and thought to be formed in the chromosphere. We present an analysis of a variety of observations of ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. A new and hitherto unknown cosmic microwave background (CMB) foreground has recently been detected. A systematic decrease in CMB temperatures around nearby large spiral galaxies points to an unknown interaction ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
We present C OSMOGLOBE Data Release 1, which implements the first joint analysis of WMAP and Planck LFI time-ordered data, processed within a single Bayesian end-to-end framework. This framework directly builds on a similar ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Tension between cosmic microwave background–based and distance ladder–based determinations of the Hubble constant H0 motivates the pursuit of independent methods that are not subject to the same systematic effects. A ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Context. Type Ia supernovae (SNe Ia) are useful distance indicators in cosmology, provided their luminosity is standardized by applying empirical corrections based on light-curve properties. One factor behind these corrections ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. The cosmological surveys that are planned for the current decade will provide us with unparalleled observations of the distribution of galaxies on cosmic scales, by means of which we can probe the underlying ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
ABSTRACT
The study of stellar flares has increased with new observations from CoRoT, Kepler, and TESS satellites, revealing the broad-band visible emission from these events. Typically, stellar flares have been ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
Three-minute oscillations are a common phenomenon in the solar chromosphere above a sunspot. Oscillations can be affected by the energy release process related to solar flares. In this paper, we report ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. Oscillations are observed to be pervasive throughout the solar corona, but it remains challenging to positively identify different wave modes. Improving this identification would provide a powerful tool for ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Cosmic birefringence is a parity-violating effect that might have rotated the plane of the linearly polarized light of the cosmic microwave background (CMB) by an angle β since its emission. This angle has recently been ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
The material composition of asteroids is an essential piece of knowledge in the quest to understand the formation and evolution of the Solar System. Visual to near-infrared spectra or multiband photometry is required to ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
ABSTRACT
We present an alternative calibration of the MagLim lens sample redshift distributions from the Dark Energy Survey (DES) first 3 yr of data (Y3). The new calibration is based on a combination of a ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Abstract
The increasing statistical power of cosmic microwave background (CMB) datasets requires a commensurate effort in understanding their noise properties. The noise in maps from ground-based instruments is ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
ABSTRACT
We measure the impact of source galaxy clustering on higher order summary statistics of weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not trace the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
ABSTRACT
While proper orbital elements are currently available for more than 1 million asteroids, taxonomical information is still lagging behind. Surveys like SDSS-MOC4 provided preliminary information for more ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
Understanding the nature of high-redshift dusty galaxies requires a comprehensive view of their interstellar medium (ISM) and molecular complexity. However, the molecular ISM at high redshifts is commonly studied using ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
We present a cross-correlation analysis between 1´resolution total intensity and polarization observations from the Atacama Cosmology Telescope (ACT) at 150 and 220 GHz and 15'' mid-infrared photometry from the Wide-field ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Aims. We validate a semi-analytical model for the covariance of the real-space two-point correlation function of galaxy clusters.
Methods. Using 1000 PINOCCHIO light cones mimicking the expected Euclid sample of galaxy ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
With two central galaxies engaged in a major merger and a remarkable chain of 19 young stellar superclusters wound around them in projection, the galaxy cluster SDSS J1531+3414 (z = 0.335) offers an excellent laboratory ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon known as Ellerman bombs (EBs). It is most common to observe EBs in the H α and H β ...
Chromospheric and coronal heating in an active region plage by dissipation of currents from braiding
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract The question of what heats the outer solar atmosphere remains one of the longstanding mysteries in astrophysics. Statistical studies of Sun-like stars reveal a correlation between global chromospheric and coronal ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
We use time-domain simulations of Jupiter observations to test and develop a beam reconstruction pipeline for the Simons Observatory Small Aperture Telescopes. The method relies on a mapmaker that estimates ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
To obtain an accurate cosmological inference from upcoming weak lensing surveys such as the one conducted by Euclid , the shear measurement requires calibration using galaxy image simulations. As it typically requires ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
We present the most comprehensive collection of stratified-in-optical-depth thermodynamic models of the lower solar atmosphere. This database, named IRIS 2+ , consists of 40,320 synthetic representative ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Observations of the millimeter sky contain valuable information on a number of signals, including the blackbody cosmic microwave background (CMB), Galactic emissions, and the Compton-y distortion due to the thermal ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Aims. In this study, we analyse the magnetic field properties of a set of 15 global magnetohydrodynamic (MHD) simulations of solar-type star dynamos conducted using the ASH code. Our objective is to enhance our understanding ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The large-scale structure of the Universe is distributed in a cosmic web. Studying the distribution and clustering of dark matter particles and haloes may open up a new horizon for studying the physics of the dark Universe. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Aims. We derived galaxy colour selections from Euclid and ground-based photometry, aiming to accurately define background galaxy samples in cluster weak-lensing analyses. These selections have been implemented in the Euclid ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Constraining the processes that drive coronal heating from observations is a difficult task due to the complexity of the solar atmosphere. As upcoming missions such as the Multi-slit Solar Explorer (MUSE) will provide ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Reverberation mapping is the leading technique used to measure direct black hole masses outside of the local Universe. Additionally, reverberation measurements calibrate secondary mass-scaling relations used to estimate ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Aims. We present an analysis of the first connection mosaic made by the SPICE instrument on board the ESA/NASA Solar Orbiter mission on March 2, 2022. The data will be used to map coronal composition that will be compared ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The mysterious nature of the dark sector of the Λ-cold-dark-matter (ΛCDM) model is one of the main motivators behind the study of alternative cosmological models. A central quantity of interest for these models is the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
This work considers which higher order modeling effects on the cosmic shear angular power spectra must be taken into account for Euclid. We identified the relevant terms and quantified their individual and cumulative impact ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The Euclid photometric survey of galaxy clusters stands as a powerful cosmological tool, with the capacity to significantly propel our understanding of the Universe. Despite being subdominant to dark matter and dark energy, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The statistical distribution and evolution of key properties of active galactic nuclei (AGN), such as their accretion rate, mass, and spin, remains a subject of open debate in astrophysics. The ESA Euclid space mission, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
Redshift measurements, primarily obtained from host galaxies, are essential for inferring cosmological parameters from type Ia supernovae (SNe Ia). Matching SNe to host galaxies using images is nontrivial, ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. Plasmoid-mediated reconnection plays a fundamental role in different solar atmospheric phenomena. Numerical reproduction of this process is therefore essential for developing robust solar models.
Aims. Our goal ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. Charged particles are constantly accelerated to non-thermal energies by the reconnecting magnetic field in the solar atmosphere. Our understanding of the interactions between the accelerated particles and their ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
We compare two different numerical methods to integrate in time spatially delocalized initial densities using the Schrödinger-Poisson equation system as the evolution law. The basic equation is a nonlinear Schrödinger ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. The mass loss experienced on the asymptotic giant branch (AGB) at the end of the lives of low- and intermediate-mass stars is widely accepted to rely on radiation pressure acting on newly formed dust grains. Dust ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
We present a catalog of 689 galaxy cluster candidates detected at significance [Math Processing Error] via their thermal Sunyaev-Zel’dovich (SZ) effect signature in 95 and 150 GHz data from the 500-square-degree SPTpol ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The shortest distance around the Universe through us is unlikely to be much larger than the horizon diameter if microwave background anomalies are due to cosmic topology. We show that observational constraints from the ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Understanding the early evolution of coronal mass ejections (CMEs), in particular their initiation, is the key to forecasting solar eruptions and induced disastrous space weather. Although many initiation mechanisms have ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Using the full 6 years of imaging data from the Dark Energy Survey, we study the surface brightness profiles of galaxy cluster central galaxies and intra-cluster light. We apply a ‘stacking’ method to over 4000 galaxy ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. The determination of accurate photometric redshifts (photo-zs) in large imaging galaxy surveys is key for cosmological studies. One of the most common approaches is machine learning techniques. These methods require ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
The presence of carbon-chain molecules in the interstellar medium (ISM) has been known since the early 1970s and > 130 such species have been identified to date, making up ∼ 43% of the total of detected ISM molecules. They ...
(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 ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
We present fluxes and light curves for a population of asteroids at millimeter wavelengths, detected by the Atacama Cosmology Telescope (ACT) over 18,000 deg 2 of the sky using data from 2017 to 2021. ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
In this paper we investigate the impact of lensing magnification on the analysis of Euclid’s spectroscopic survey using the multipoles of the two-point correlation function for galaxy clustering. We determine the impact ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Context. AD Leo is a young and active M dwarf with high flaring rates across the X-ray-to-radio bands. Flares accelerate particles in the outer coronal layers and often impact exo-space weather. Wide-band radio dynamic ...
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
(Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2024)
Abstract
Small-scale, newly emerging internetwork (IN) magnetic fields are considered a viable source of energy and mass for the solar chromosphere and possibly the corona. Multiple studies show that single events ...