Related papers: Galactic disc warps due to intergalactic accretion…
The origin of the spins of giant planets is an open question in astrophysics. As planets and stars accrete from discs, if the specific angular momentum accreted corresponds to that of a Keplerian orbit at the surface of the object, it is…
Growth rates for gravitational instabilities in a thick disk of gas and stars are determined for a turbulent gas that dissipates on the local crossing time. The scale heights are derived from vertical equilibrium. The accuracy of the usual…
We simulate the viscous evolution of an accretion disc around a spinning black hole. In general any such disc is misaligned, and warped by the Lense-Thirring effect. Unlike previous studies we use effective viscosities constrained to be…
Star formation is thought to be triggered by the gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…
After their initial formation, disk galaxies are observed to be rotationally stable over periods of >6 Gyr, implying that any large velocity disturbances of stars and gas clouds are damped rapidly on the timescale of their rotation.…
Different from Milky-Way-like galaxies, discs of gas-rich galaxies are clumpy. It is believed that the clumps form because of gravitational instability. However, a necessary condition for gravitational instability to develop is that the…
We examine the behaviour of an axisymmetric galactic dynamo model with a radial accretion flow in the disc. We also introduce a vertical magnetic flux through the galactic midplane, to simulate the presence of a large scale magnetic field…
We present a numerical model for the evolution of a protostellar disc that has formed self-consistently from the collapse of a molecular cloud core. The global evolution of the disc is followed for several million years after its formation.…
In this contribution I summarize our current knowledge of the nature and significance of starburst-driven galactic superwinds. These flows are driven primarily by the kinetic energy supplied by supernovae. Superwinds are complex, multiphase…
Recent observations have shown that most of the warps in the disk galaxies are asymmetric. However there exists no generic mechanism to generate these asymmetries in warps. We have shown that a rich variety of possible asymmetries in the…
Predicting the local flux of dark matter particles is vital for dark matter direct detection experiments. To date, such predictions have been based on simulations that model the dark matter alone. Here we include the influence of the…
We consider misaligned accretion discs formed after tidal disruption events occurring when a star encounters a supermassive rotating black hole. We use the linear theory of warped accretion discs to find the disc shape when the stream…
Spiral shocks are potentially a major source of turbulence in the interstellar medium. To address this problem quantitatively, we use numerical simulations to investigate gas flow across spiral arms in vertically stratified,…
We perform a critical re-analysis and discussion of recent results presented in the literature which interpret the CMa overdensity as the signature of an accreting dwarf galaxy or a new substructure within the Galaxy. Several issues are…
The Galactic Centre is known to have undergone a recent star formation episode a few Myrs ago, which likely produced many T Tauri stars hosting circumstellar discs. It has been suggested that these discs may be the compact and dusty ionized…
We assume that the individual stars which are located at the peripheral parts of the spiral galaxies are experiencing a drag force acting upon them radially. Such a force might be produced by some sort of a dynamically generated viscous…
In the first part of this article we show how observations of the chemical evolution of the Galaxy: G- and K-dwarf numbers as functions of metallicity, and abundances of the light elements, D, Li, Be and B, in both stars and the…
We investigate the role of stellar mass in shaping the intrinsic thickness of galaxy discs by determining the probability distribution of apparent axis ratios (b/a) for two different samples that probe the faint end of the galaxy luminosity…
A clear understanding of the chemical processing of matter, as it is transferred from a molecular cloud to a planetary system, depends heavily on knowledge of the physical conditions endured by gas and dust as these accrete onto a disk and…
Accretion of gas from the cosmic web to galaxy halos and ultimately their disks is a prediction of modern cosmological models but is rarely observed directly or at the full rate expected from star formation. Here we illustrate possible…