UVicSpace

Dwarfs among giants: exploring environmental impacts on dwarf galaxies with the solo survey

Show simple item record

dc.contributor.author Higgs, Clare
dc.date.accessioned 2021-12-02T21:51:52Z
dc.date.available 2021-12-02T21:51:52Z
dc.date.copyright 2021 en_US
dc.date.issued 2021-12-02
dc.identifier.uri http://hdl.handle.net/1828/13563
dc.description.abstract This thesis attempts to untangle, as best as possible, the importance of internally-driven evolutionary mechanisms relative to externally-driven effects, in shaping the structure and properties of the smallest observable galaxies. All galaxies are influenced by internal processes, such as feedback from star formation and the infall of gas or lack thereof, as well as environmental processes, like tides and ram pressure stripping. The smallest galaxies - dwarfs - are highly susceptible to all such processes, and their resulting structure is the summation of all prior events. I use nearby dwarf galaxies of the Local Group as test cases, focusing on those which are separated from the massive galaxies (like the Milky Way) and can be considered as "isolated''. These dwarfs are observed as part of the Solitary Local (Solo) Dwarf Galaxy Survey. Solo dwarfs will have spent the majority of their time as isolated systems, hence their properties should generally reflect their "intrinsic nature", unperturbed and unaffected by interactions with other systems. This survey was designed to focus on the old stellar populations present in these galaxies, in order to characterize their faint and extended structures. These old stellar populations should carry the hallmarks of the dwarfs' histories. By comparing the observed properties of Solo dwarfs with dwarfs currently in close proximity to a large host galaxy (i.e., the M 31 and Milky Way satellites), it should be possible to determine what aspects of the properties of dwarfs are most affected by environmentally-driven processes. The Local Group is the ideal regime in which to study these faint features, as the dwarfs' close proximity to us presents an opportunity to fully characterize these galaxies. However, the number of dwarfs in the Local Group is limited, with several galaxies (e.g. IC 10 or Sag dSph) being the unique example of their "type" locally observable. This limited sample emphasizes the need for careful, homogeneous observations and analysis, such that comparisons between this small, yet highly diverse, snapshot of galaxies accurately reflects the true nature of these dwarfs. I have homogeneously analyzed the 12 closest Solo dwarfs observable from the northern hemisphere, resulting in a consistently derived dataset. I determine fundamental properties, like distances, and characterize the structure of the dwarfs. I explore the possibility that the dwarfs may be more consistent with a two component profile, rather than one, finding that they are largely well characterized by a single Sérsic profile. I then compare these isolated dwarfs with the well-studied satellites of the Milky Way and M 31, primarily using two other homogeneous surveys; the MegaCam Survey of Outer Halo Objects and the Pan-Andromeda Archaeological Survey respectively. Examining each property (e.g. ellipticity, central surface brightness, or Sérsic radius) individually, we find no statistically significant differences between each group. However, when considering parameters in combination (e.g. absolute magnitude as a function of Sérsic radius), we see increased scatter in the satellite population, indicative of the impact of a massive host galaxy on the dwarfs, likely via tidal effects. The comparison between satellites and isolated dwarfs hones in on the impact of a massive galaxy in close proximity. Of course, processes within and surrounding the dwarf itself can also alter the dwarf. I look at the star formation histories and gas content of the dwarfs to explore the connection between internal and external processes in these small galaxies. Finally, I search for substructure in the form of satellites of dwarf galaxies, globular clusters and extended tidal features, all which inform about the dwarf's isolation, environment and history. Collectively, I generate comprehensive and detailed inspections of Local Group dwarfs and aim to understand them as products of their environment. en_US
dc.language English eng
dc.language.iso en en_US
dc.rights Available to the World Wide Web en_US
dc.subject galaxies en_US
dc.subject galaxy formation en_US
dc.subject dwarf galaxies en_US
dc.subject stellar structure of dwarf galaxies en_US
dc.title Dwarfs among giants: exploring environmental impacts on dwarf galaxies with the solo survey en_US
dc.type Thesis en_US
dc.contributor.supervisor McConnachie, Alan
dc.contributor.supervisor Venn, Kimberley Ann
dc.degree.department Department of Physics and Astronomy en_US
dc.degree.level Doctor of Philosophy Ph.D. en_US
dc.identifier.bibliographicCitation Higgs C.R., McConnachie A.W., Annau N., Irwin M., Battaglia G., Côté P., Lewis G.F. and Venn, K. Solo dwarfs II: the stellar structure of isolated Local Group dwarf galaxies, 2021, MNRAS, 503, 176. doi:10.1093/mnras/stab002 en_US
dc.identifier.bibliographicCitation Higgs C.R., McConnachie A.W. Solo dwarfs IV: comparing and contrasting satellite and isolated dwarf galaxies in the Local Group, 2021, MNRAS, 506, 2766. doi:10.1093/mnras/stab1754 en_US
dc.description.scholarlevel Graduate en_US


Files in this item

This item appears in the following Collection(s)

Show simple item record

Search UVicSpace


Browse

My Account

Statistics

Help