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The Planes of Satellites Problem is an open question within the field of galaxy formation. It is based on the observations that the Milky Way's satellites, as well as those around the Andromeda (M31) galaxy, align in planes. This applies both to the satellites' positions lying close to the plane of best fit, and to the satellites' orbital planes aligning within a narrow angle. Such pla
We probe the implications of 5 different previously developed models of the evolution of the Milky Way’s radial metallicity gradient for radial migration of stars observed today between 5kpc < R < 12kpc. Our sample contains 7167 giant stars, with metallicities and radial velocities obtained from APOGEE DR14, full 5-parameter kinematic information from Gaia DR2, and ages derived in Martig et al. 20
A star forms with a surrounding protoplanetary disk after the collapse of a molecular cloud core. Subsequently, over a period of several Myr this protoplanetary disk of dust and gas is accreted onto the host star. We model the formation and evolution of such a protoplanetary disk using a one-dimensional numerical model. We find that disks form on a time scale of less than 1 Myr and that the size a
The consensus in the field is that we have a pretty good understanding of the physics behind star formation and evolution. So far, the models that have been created characterize the different collections of stars in our Milky Way galaxy with decent accuracy, and they have allowed for humanity to obtain insights into how our universe evolved. However, the author believes that our current techniques
Short gamma-ray bursts are often observed at large spatial offsets from their host galaxies. Neutron star mergers in double neutron star binaries have also recently been confirmed as a progenitor of short gamma-ray bursts (Abbott et al. 2017). We attempt to constrain uncertainties in the evolution of burst-producing neutron star binaries by generating a distribution of burst offsets from the neutr
Planets that orbit their host star closely experience tidal forces due to the strength of gravity not being uniform all over the planet. This leads to effects such as tidal spin synchronization, tidal eccentricity damping and tidal semi-major axis damping. This project aims to study how the time scales for these phenomena are affected by the planetary parameters such as mass, radius and the tidal
One of the biggest mysteries astronomers wish to unveil is the formation and evolution of galaxies. Properties of our own galaxy, the Milky Way, can provide great insight into these. The star formation rate (SFR) and whether it varies with distance from the galactic centre (GC), is one of these properties. Studies indicate that the SFR is higher in the bulge region than in the local thick disk of
The observed high orbital eccentricities of many giant exoplanets is thought to be the result of gravitational scattering between planets. Outcomes of planet-planet scattering can result in some planets being lost by ejections into interstellar space, or collisions between planets or with the star. The likelihood of collisions for a planet with a certain mass, increases with larger radii. After p
In a phase of instability during the dynamical evolution of some multiple exoplanetary systems, exchange of angular momentum and/or energy through gravitational interactions between planets will lead to alterations of their orbital properties. In some cases, planetary orbits end up crossing, which leads to close encounters between two planets. In turn, they undergo a planet--planet scattering even
The interstellar medium of both local and distant disc galaxies is observed to be supersonically turbulent and the turbulent motion of the gas is thought to be important for galaxy formation and evolution, particularly as a key ingredient for star formation. Consequently, this generates a striking relation between the star formation rate (SFR) and gas velocity dispersion ($\sigma_{\rm g}$; a measu
Interactions play a crucial role in determining how galaxies evolve in terms of their morphologies and star formation histories, since the majority of the known galaxies in the nearby Universe are found to exist in groups. Compact groups of galaxies are of particular interest as they contain a small number of galaxies in dense configurations and host repeated interactions between them, enabling us
Planetary embryos grow by the accretion of solid dust-material, ranging from cm- to m-sized pebbles up to km-sized planetesimals. However, the underlying size-distribution of the accreted material is poorly understood. When the pebbles and planetesimals encounter a protoplanet, they are subjected to the gaseous environment of the protoplanetary envelope. Because of the drag-force from the gas, the
5 oktober 2026 14:15 till 15:15 | Seminarium Lund University’s Profile Areas Nature-Based Future Solutions and Human Rights invite you to a joint seminar and fika with Linnéa Nordlander, recently appointed Global Research Fellow at the Faculty of Law. In her talk, Linnéa will present her research on the intersection of human rights, climate change, and just transition. The event also aims to conti
https://www.lu.se/evenemang/seminar-profile-area-networking-human-rights-climate-change-and-just-transition - 2026-10-08
We propose an approximate scheme based on a saddle point approximation of propagators in higher order perturbation calculation. This scheme is applied to a general expression for one-loop scalar functions, and thereafter used to calculate the anomalous magnetic moment of the electron. The scheme is shown to be increasingly precise as the number of propagators increase, spanning a precision of 0.72
The problems of the standard model are reviewed and the motivations for introducing supersymmetry are discussed. The basic theory behind supersymmetry is described briefly, followed by an introduction of two realistic supersymmetric models; the Minimal SuperSymmetric Model (MSSM) and its proposed extension, the NMSSM. Some details of the NMSSM are stated and some constraints on parameters are desc
