When you hit a drum, it vibrates and emits a sound. When you hit a black hole, it also vibrates and emits gravitational waves. Hitting black holes is not very easy, but fortunately nature does it for us with black hole collisions. Remarkably, general relativity predicts that the vibration of a black hole is rather simple. The spectrum of vibrational modes depends only on the mass and angular...
Intermittent fluctuations with large amplitudes compared to the background level can arise in far-from equilibrium and turbulent systems as well as due to sudden, large-amplitude forcing [1, 2]. Conditional averaging has been a much-used tool for finding amplitudes of intermittent events and the waiting time between them [2]. However, conditional averaging requires both significant amplitude...
We aim to estimate the Stochastic Gravitational Wave Background (SGWB), generated by a given stellar origin binary black hole (SOBBH) population, on the LISA strain.
We start by simulating a SOBBH catalogue that will simulate as close as possible what the LISA detector would be able to observe at the time of launch, in order to do so, we implement the probability density functions (PDFs) of...
In order to estimate the global temperature response and climate sensitivity to radiative forcing, volcanic activity is an important testbed. This work uses a non-parametric method for estimating the temperature response due to volcanic forcing from a simulation of the NorESM model [1]. In addition, this response will be convolved with reconstructed volcanic forcing and compared to temperature...
The information about the electron population emanating from a helicon source plasma is important in order to understand the formation of the current-free double layer (CFDL) between the source and the downstream region of a helicon plasma. The electrons need an energy higher than the potential drop across the CFDL to escape downstream from the source, and at these energies the signal of a...
One of the next big steps in cosmology is the detection of inflationary gravitational waves from the Big Bang. These waves were created from the exponential expansion of the universe, just parts of a nanosecond after its birth. Signals from these ripples in space-time are extremely weak and have proved very hard to detect. One future telescope aiming to detect this signal is the JAXA’s...
UiO has been operating all-sky imagers in the arctic regions for over 20 years. Between October and March images are taken at two different wavelengths every 5-30 seconds, resulting in a collection of almost 8 million images taken in Ny-Ålesund and Longyearbyen since 2006. These images are supplemented by magnetometer measurements, information about GNSS-signal quality of satellites in the...
Black Holes are possibly the most enigmatic objects in our Universe. From their detection in gravitational waves upon their mergers, to their snapshot eating at the centers of galaxies, black hole astrophysics has undergone an observational renaissance in the past 5 years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects of the elusive...
På CERN har LHC vårrengjøring, også kjent som "Long Shutdown 2".
En periode dedikert til vedlikehold og oppgradering av maskiner, magneter og eksperimenter.
ALICE eksperimentet oppgraderer flere av detektorene sine, og er snart klar for å slåes på for
sitt tredje fysikk "turnus" som skal kjøre i tre år.
Etter dette kommer "Long Shutdown 3" i 2025-2027, hvor minst en ny detektor skal stå...
Vanadium spinel oxides with formula $AV_2O_4$ (A = Fe, Co, etc.) have attracted much interest since they exhibit various intriguing physical properties, particularly in studying the role of orbital degrees of freedom in frustrated antiferromagnets [1,2]. However, very little attention has been paid to vanadium inverse spinel oxides $A_2VO_4$(A = Fe or Co). We report investigations on one of...
Much of what we know about large-scale variations in the solar wind-magnetosphere-ionosphere-thermosphere system comes from statistical analyses of average patterns and responses via observational data sets built up over long periods of time. With the advent in the past 10–20 years of large observational networks and consortia such as SuperDARN, SuperMAG, and the Iridium satellites, we are...
In this work the β phase of Vanadiumoxosulphate (VI) (β-VOSO4) crystal was used to study the physical properties of low dimensional magnetism in spin ½ chains.
Structural analysis from X-ray diffraction and neutron diffraction performed on the sample, confirm that it crystallizes in the Pnma (62) space group. β-VOSO4 has V4+ bounded to six oxygen that gives it an octahedral configuration...
Studying the production of charmonium states in hadronic collisions may improve our understanding of the theory describing the strong interaction, known as quantum chromodynamics (QCD). The formation of heavy charm quark pairs takes place during the initial hard partonic scattering and can therefore be calculated using perturbative QCD, while the evolution into a colorless bound state is a...
The auroral electrojet is traditionally measured remotely with magnetometers on ground or in low Earth orbit (LEO). The sparse spatial coverage of measurements, combined with a vertical distance (~100 km to ground and typically >300 km to LEO satellites) means that smaller scale sizes cannot be detected. Because of this, our understanding of the spatiotemporal characteristics of the...
Inclusions of metallocenes into host frameworks of urea and thiourea have been studied widely for years due to their interesting structure and elusive arrangement of guest molecules.
Since conventional structure solution procedures can only provide a time-averaged picture, an alternative «bottom-up» approach was proposed in which an imperfect crystal structure is built in Mathematica via...
In hadronic collisions, heavy-flavour quarks (beauty and charm) are produced in hard-scattering processes with large momentum transfer. The production of hadrons containing beauty quarks provides a very important test of perturbative QCD calculations in pp collisions. Measurement of beauty-hadron production in heavy-ion collisions is a unique tool to investigate the properties of the...
We investigate the effect of destruction processes of cosmic dust particles on their propagation near the Sun. This work is motivated by on-going observations of two spacecraft which explore the inner solar system and the vicinity of the Sun: the NASA Parker Solar Probe (PSP) and ESAs Solar Orbiter (SolO). SolO makes observations of the Sun and in-situ measurements from elliptic orbits which...
$SrTm_2O_4$ belongs to the family of $SrLn_2O_4$ (Ln - rare-earth ions), where many unconventional magnetic phenomena have been discovered [1]. However, $SrTm_2O_4$ does not show either long-range or short-range order down to 65mK[2].On the other hand, our muon spin rotation/relaxation (µSR) results show signs of spontaneous magnetic ordering even at near room temperatures with no sign of...
Using incoherent scatter radar (ISR) to determine the neutral wind velocity in the ionosphere has been done for nearly 50 years. The method for finding the velocity of the neutral wind uses the ion velocity which is one of the parameters that the ISRs measure. The ion velocity is connected to the neutral wind velocity through collisions, and to electrical field through the Lorentz force where...
At the ALICE experiment at CERN, quark-gluon plasma (QGP) is produced in the early stages of ultra-relativistic heavy ion collisions. Prior to the formation of QGP, heavy quarks and antiquarks (charm and beauty) are created in the initial hard scattering of the partons of the heavy ions. They subsequently move through the QGP, their numbers remaining conserved while they interact with the hot...
Heat exhaust in the boundary region of fusion experiments remains to this day the biggest challenge towards harvesting fusion power. Transport of particles and heat in this region is dominated by radial motion of coherent structures known as blobs [1].
Long time series obtained by fixed point probe measurements in recent experiments reveal highly intermittent fluctuations in the ion...
The validity of the Brink-Axel hypothesis, which is especially important for numerous astrophysical calculations, is addressed for $^{116,120,124}$Sn below the neutron separation energy by means of three independent experimental methods. The $\gamma$-ray strength functions (GSFs) extracted from primary $\gamma$-decay spectra following charged-particle reactions with the Oslo method and with...
The boundary of magnetically confined plasmas is in a strongly fluctuating state due to the propagation of large amplitude coherent structures. A stochastic single-point model based on the superposition of un-correlated pulses has been successfully validated across different reactors. We extend this model to describe two-point measurements. This model can describe experimental techniques such...
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Mesospheric bores are non-linear solitary type internal waves observed in the 80 – 100 km region of Earth atmosphere, the upper mesosphere. The existence of these waves is known for more than two decades. Researchers have attained a reasonable understanding on the nature of such waves. However, some of the observed characteristics of these waves cannot be explained based on existing knowledge....
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Jet interactions in a hot QCD medium created in heavy-ion collisions are conventionally assessed by measuring the modification of the distributions of jet observables with respect to the proton-proton baseline. However, the steeply falling production spectrum introduces a strong bias toward small energy losses that obfuscates a direct interpretation of the impact of medium effects in the...
Space plasmas display fluctuations and nonlinear behavior at a broad range of scales, being in most cases in a turbulent state. The majority of these plasmas are also considered to be heated, with dissipation of turbulence as a possible explanation. Despite of many studies and advances in research, many aspects of the turbulence, heating and their interaction with several space plasma...
The energy transfer from the solar wind to the Earths magnetosphere fuels the Energetic Particle Precipitation (EPP). EPP refers to highly energetic electrons and protons that are accelerated into the atmosphere, mainly in the polar regions. This energetic particles influence the atmospheric chemical composition by producing nitric oxides(NOx) and hydrogen oxides (HOx), among others, which...
We recently proposed a novel thermal production mechanism for dark matter based on the idea that dark matter particles $\chi$ can transform (`infect') heat bath particles $\psi$: $\chi \psi \rightarrow \chi \chi$. For a small initial abundance of $\chi$ this induces an exponential growth in the dark matter number density, closely resembling the epidemic curves of a spreading pathogen after an...
GAMBIT is an open-source framework for performing large-scale statistical analyses of new theories in particle physics. In this talk I will introduce the GAMBIT Universal Model Machine (GUM), which is a new tool for automatically generating model-specific collider, dark matter, decay and spectrum code for GAMBIT, starting from the Lagrangian-level definition of a new theory. This new...
Energetic particles from the Sun or the Earth’s magnetosphere penetrate into the upper or middle atmosphere, altering its chemical properties, which results in a reduction of ozone. As ozone is important in the energy budget in this region it can affect the temperature and winds in this region. These winds have links to our weather system, and it is speculated that it might affect polar...
By utilising measurements from twenty ground magnetometer stations in Fennoscandia, divergence-free ionospheric currents above this region are modelled using spherical elementary currents (SECS). New modelling techniques are implemented that coerce the model to find a solution that resembles the resolvable ionospheric currents. The divergence-free currents are evaluated along the $105^\circ$...
I will explain how in modern mathematical physics tools of Geometry can be used to inform about Quantum Field Theory and vice versa. This can particularly be useful in the realm of strongly coupled field theories, although usually with some level of supersymmetry assumed.
In this study, we use the first data from the all-sky camera installed in Antarctica at the Norwegian Research Station Troll. The auroral all-sky camera calibration was calibrated. Together with the ground-based TEC and scintillation receiver located there, a comprehensive analysis of the reasons for observing scintillations over the Troll station during the period of geomagnetic disturbances...
