Galaxy discs as accretion discs
Typ
Examensarbete för masterexamen
Program
Publicerad
2021
Författare
Halldórsson, Bergur
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Accretion and accretion discs around compact objects such as black holes and neutron
stars are well studied phenomena, but galactic discs have rarely been examined
as accretion discs, despite showing clear evidence of radial mass inflow. Rotation
curves, radial velocity and radial mass flux data for ten different spiral galaxies were
acquired from Schmidt et al. (2016) who in turn were working with data from The
HI Nearby Galaxy Survey (THINGS). The data are used to calculate several quantities
which are essential for accurately modelling accretion discs, with a focus on
two different versions of the parameter, which describes the efficiency with which
turbulence acts as a source of "effective" viscosity in the accretion process. These
quantities are then analysed with consideration for the properties of the galaxies
and the structures present. While there was no obvious connection found between
the value of and the spiral structure present throughout the disc structures with
clearer radial limits such as rings and bars were found to have definite effects on the
value of .
Beskrivning
Ämne/nyckelord
alpha-disc model, Spiral galaxies