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The role of large scale flows in molecular cloud formation in spiral galaxies
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dc.contributor.advisor | Bonnell, Ian Alexander | |
dc.contributor.author | Ramon Fox, Felipe Gerardo | |
dc.coverage.spatial | xxiii, 223 p. | en_US |
dc.date.accessioned | 2019-05-31T16:07:37Z | |
dc.date.available | 2019-05-31T16:07:37Z | |
dc.date.issued | 2019-06-24 | |
dc.identifier.uri | https://hdl.handle.net/10023/17793 | |
dc.description.abstract | Star formation begins on the large scales of a galaxy and takes place on the smallest scales. As the interstellar gas flows into a spiral arm, it forms a shock where the change in density, coupled to self-gravity and thermal instabilities, leads to the formation of high density structures where molecular clouds grow. It is important to understand the role of large-scale flows in assembling these clouds. This work explores the gas flows in spiral arms to understand its role on molecular cloud formation comparing between grand-design and flocculent galaxies. A set of high-resolution smoothed particle hydrodynamics (SPH) simulations are used. One simulation evolves the gas in a potential including a halo, stellar disc, and spiral arms. The second simulation evolves the gas in an N-body stellar disc and bulge within a fixed halo potential. The first and second models are representative of grand-design and flocculent galaxies, respectively. The third simulation is a high-resolution simulation of a region of gas flowing in a spiral arm based on the simulations of Bonnell et al. (2013), which follows in more detail the local cloud dynamics. In the global models, the mass resolution is about 45M⊙ per gas particle and in the spiral simulation, about 0.6M⊙. The results show that in both the grand-design and flocculent models, the gas is shocked as it flows through an arm. The N-body model shows flow characteristics qualitatively similar to the spiral potential model but with more variations due to the potentials arm-to-arm variations. Clouds are identified using a friends-of-friends algorithm to catalogue clumps above a given density threshold. These have non-negligible streaming motions and their properties are consistent with observed mass-radius and size-velocity dispersion relations. | en_US |
dc.description.sponsorship | "This work was supported by the ERC ECOGAL project under grant number 291277. I also thank the University of St. Andrews for supporting me with a St. Leonards Scholarship." -- Acknowledgements | en |
dc.language.iso | en | en_US |
dc.publisher | University of St Andrews | |
dc.relation | The role of large scale flows in molecular cloud formation in spiral galaxies (Thesis data) Ramon Fox, F.G., University of St Andrews, 22 May 2019 DOI: https://doi.org/10.17630/0b6aa0a8-d46a-4660-ad87-320c982746ee | en |
dc.relation.uri | https://doi.org/10.17630/0b6aa0a8-d46a-4660-ad87-320c982746ee | |
dc.rights | Attribution-NonCommercial-NoDerivatives 4.0 International | * |
dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | * |
dc.subject | Hydrodynamics | en_US |
dc.subject | Interstellar medium -- Kinematics and dynamics | en_US |
dc.subject | Interstellar medium -- Molecular clouds -- Formation | en_US |
dc.subject | Galaxies -- Kinematics and dynamics | en_US |
dc.subject | Milky Way -- Structure | en_US |
dc.subject | Astrophysics -- Astrophysics of galaxies | en_US |
dc.subject.lcc | QB791.4R2 | |
dc.subject.lcsh | Molecular clouds | en |
dc.subject.lcsh | Galactic dynamics | en |
dc.subject.lcsh | Spiral galaxies | en |
dc.title | The role of large scale flows in molecular cloud formation in spiral galaxies | en_US |
dc.type | Thesis | en_US |
dc.contributor.sponsor | European Research Council (ERC) | en_US |
dc.contributor.sponsor | University of St Andrews. St Leonard's College | en_US |
dc.type.qualificationlevel | Doctoral | en_US |
dc.type.qualificationname | PhD Doctor of Philosophy | en_US |
dc.publisher.institution | The University of St Andrews | en_US |
dc.identifier.doi | https://doi.org/10.17630/10023-17793 |
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