Persistent Link:
http://hdl.handle.net/10150/280672
Title:
Alignment of galactic components in models of galaxy formation
Author:
Bailin, Jeremy
Issue Date:
2004
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
In this thesis, we study the relationship between the angular momentum and shape of galactic disks, satellite galaxies, dark matter halos, and large scale structure using N-body simulations in the context of current models of galaxy formation. In warped galactic disks, the angular momenta of the inner and outer disk are misaligned. We have calculated the torques a misaligned halo imparts on an embedded galactic disk. N-body simulations of disks subject to torques of this strength indicate that the disk tilts in response and develops a trailing warp of the same magnitude as the Milky Way warp. We have investigated whether the warp of the Milky Way's disk is caused by nearby satellite galaxies. The misaligned warp angular momentum is anti-aligned with the orbital angular momentum of the Sgr dSph, and is of the same magnitude. This suggests that Sgr is responsible for the warp. However, N-body simulations of such disk-satellite interactions indicate that the warps excited by Sgr with its current mass and orbit are much smaller than the warp of the Milky Way. The alignment of the shapes and angular momenta of dark matter halos and the large scale environment has been studied in cosmological dark matter simulations. We have analyzed several late snapshots of such a simulation and found rotation of the triaxial figure of the halos. The figure rotates about the minor axis in most cases, at a rate that follows a log-normal distribution centred on Ωp = 0.148 h km s⁻¹ kpc⁻¹. Halos have triaxial shapes that become more spherical at larger radii. The principal axes of individual halos show strong internal alignment, as does the angular momentum, which is usually oriented along the minor axis. This alignment is not perfect, and the median misalignment is large enough to cause galactic warps. The minor axes of halos tend to point perpendicular to filaments and sheets. Major axes show a weaker tendency to point along filaments. These alignments are much stronger for higher mass halos. The angular momenta of galaxy mass halos tend to point along filaments and sheets, while those of group mass halos point perpendicular to the surrounding mass distribution.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Physics, Astronomy and Astrophysics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Astronomy
Degree Grantor:
University of Arizona
Advisor:
Steinmetz, Matthias

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleAlignment of galactic components in models of galaxy formationen_US
dc.creatorBailin, Jeremyen_US
dc.contributor.authorBailin, Jeremyen_US
dc.date.issued2004en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIn this thesis, we study the relationship between the angular momentum and shape of galactic disks, satellite galaxies, dark matter halos, and large scale structure using N-body simulations in the context of current models of galaxy formation. In warped galactic disks, the angular momenta of the inner and outer disk are misaligned. We have calculated the torques a misaligned halo imparts on an embedded galactic disk. N-body simulations of disks subject to torques of this strength indicate that the disk tilts in response and develops a trailing warp of the same magnitude as the Milky Way warp. We have investigated whether the warp of the Milky Way's disk is caused by nearby satellite galaxies. The misaligned warp angular momentum is anti-aligned with the orbital angular momentum of the Sgr dSph, and is of the same magnitude. This suggests that Sgr is responsible for the warp. However, N-body simulations of such disk-satellite interactions indicate that the warps excited by Sgr with its current mass and orbit are much smaller than the warp of the Milky Way. The alignment of the shapes and angular momenta of dark matter halos and the large scale environment has been studied in cosmological dark matter simulations. We have analyzed several late snapshots of such a simulation and found rotation of the triaxial figure of the halos. The figure rotates about the minor axis in most cases, at a rate that follows a log-normal distribution centred on Ωp = 0.148 h km s⁻¹ kpc⁻¹. Halos have triaxial shapes that become more spherical at larger radii. The principal axes of individual halos show strong internal alignment, as does the angular momentum, which is usually oriented along the minor axis. This alignment is not perfect, and the median misalignment is large enough to cause galactic warps. The minor axes of halos tend to point perpendicular to filaments and sheets. Major axes show a weaker tendency to point along filaments. These alignments are much stronger for higher mass halos. The angular momenta of galaxy mass halos tend to point along filaments and sheets, while those of group mass halos point perpendicular to the surrounding mass distribution.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPhysics, Astronomy and Astrophysics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSteinmetz, Matthiasen_US
dc.identifier.proquest3158068en_US
dc.identifier.bibrecord.b47906698en_US
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