Sökning: "accretion"
Visar resultat 21 - 25 av 67 avhandlingar innehållade ordet accretion.
21. Attraction and Rejection : On the love–hate relationship between stars and black holes
Sammanfattning : Solitary stars wandering too close to the supermassive black hole at the centre of their galaxy may become tidally disrupted, if the tidal forces due to the black hole overcome the self-gravity holding the star together. Depending on the strength of the encounter, the star may be partially disrupted, resulting in a surviving stellar core and two tidal arms, or may be completely disrupted, resulting in a long and thin tidal stream expected to fall back and circularize into an accretion disc (the two cases are illustrated on the cover of this thesis). LÄS MER
22. Methanol masers reveal the magnetic field of a high mass protostar
Sammanfattning : The role played by magnetic fields in high-mass star formation is not yet fully clear. Theoretical simulations have shown that magnetic fields appear to suppress fragmenta- tion in the star forming cloud, to enhance accretion via disc and to provide feedback in the form of outflows and jets. LÄS MER
23. Young stars and outflows : case studies of three different regions
Sammanfattning : Mass is clearly the most important parameter of a star as it determines the phases it will go through, its physical parameters, the elements produced and its life span. Two important processes that occur simultaneously in young stars are directly related to the final mass a star ends up with; the accretion of material onto the star from a circumstellar disk and the bipolar outflow of material from the star. LÄS MER
24. Modelling and analyzing strong-field effects in quantum plasma
Sammanfattning : Under the extreme conditions that can be found around dense stars and in the accretion discs of black holes, several strong-field quantum phenomena dominate the dynamics of the plasma. This includes the creation of matter and anti-matter from the vacuum (Schwinger mechanism), radiation reaction and Landau quantization. LÄS MER
25. A High Resolution Study of the LINER Galaxy NGC5218
Sammanfattning : Low Ionisation Nuclear Emission-line Regions (LINERs)are found in one third of the galaxies in the local bright galaxy population. The LINERs typically recide in the central parts of their host galaxies, and occur in early type elliptical galaxies as well as late type spiral galaxies. LÄS MER
