Show simple item record

dc.contributor.supervisor English, Jayanne (Physics & Astronomy) en
dc.contributor.author Wiegert, Theresa B. V.
dc.date.accessioned 2011-01-19T20:29:35Z
dc.date.available 2011-01-19T20:29:35Z
dc.date.issued 2011-01-19T20:29:35Z
dc.identifier.uri http://hdl.handle.net/1993/4377
dc.description.abstract Although galaxy interactions cause dramatic changes, galaxies also continue to form stars and evolve when they are isolated. The dark matter (DM) halo may influence this evolution since it generates the rotational behaviour of galactic disks which could affect local conditions in the gas. Therefore we study neutral hydrogen kinematics of non-interacting, nearby spiral galaxies, characterising their rotation curves (RC) which probe the DM halo; delineating kinematic classes of galaxies; and investigating relations between these classes and galaxy properties such as disk size and star formation rate (SFR). To generate the RCs, we use GalAPAGOS (by J. Fiege). My role was to test and help drive the development of this software, which employs a powerful genetic algorithm, constraining 23 parameters while using the full 3D data cube as input. The RC is here simply described by a tanh-based function which adequately traces the global RC behaviour. Extensive testing on artificial galaxies show that the kinematic properties of galaxies with inclination >40 degrees, including edge-on galaxies, are found reliably. Using a hierarchical clustering algorithm on parametrised RCs from 79 galaxies culled from literature generates a preliminary scheme consisting of five classes. These are based on three parameters: maximum rotational velocity, turnover radius and outer slope of the RC. To assess the relationship between DM content and the kinematic classes, we generate mass models for 10 galaxies from the THINGS and WHISP surveys, and J. Irwin's sample. In most cases mass models using GalAPAGOS RCs were similar to those using traditional ``tilted-ring'' method RCs. The kinematic classes are mainly distinguished by their rotational velocity. We confirm correlations between increasing velocity and B-magnitude, optical disk size, and find earlier type galaxies among the strong rotators. SFR also increases with maximum rotational velocity. Given our limited subsample, we cannot discern a trend of velocity with DM halo properties such as M_halo/M_baryon. Using this strategy on upcoming large databases should reveal relationships between the DM halo and our kinematic classification scheme. If NGC 2841, NGC 3521 and NGC 5055 are understood to have declining RC after further investigation, this cannot be explained by the usual morphology scenarios. en
dc.format.extent 6466224 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject astronomy en
dc.subject neutral hydrogen en
dc.subject rotation curves en
dc.title Spiral galaxy HI models, rotation curves and kinematic classifications en
dc.degree.discipline Physics and Astronomy en
dc.contributor.examiningcommittee Safi-Harb, Samar (Physics & Astronomy) Gwinner, Gerald (Physics & Astronomy) Zetner, Peter (Physics & Astronomy), Sherriff, Barbara (Geological sciences) Carignan, Claude (Département de physique, Université de Montréal) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note February 2011 en


Files in this item

This item appears in the following Collection(s)

Show simple item record

View Statistics