Galactic Building Blocks: Dwarf Galaxies Near and Far
Abstract
The work I have done during my thesis has consisted of both observational and theoretical projects involving dwarf galaxies and Cold Dark Matter (CDM) sub-structure both around the Milky Way and in redshift z∼0.1 galaxies. The dwarf galaxies around the Milky Way are distributed in a so-called vast polar structure (VPOS) that may be in conflict with ΛCDM simulations. For this project, we seek to investigate two key questions to determine if the VPOS poses a serious challenge to the ΛCDM paradigm on galactic scales. First, we ask which dwarf galaxy satellites drive the fit to the VPOS and create planar structure. Second, we ask if the VPOS remains coherent as a function of time. Using the measured HST proper motions and associated uncertainties, we integrate the orbits of the classical Milky Way satellites backwards in time and find that for the mean of the measured HST proper motions, the VPOS deteriorates in less than a dynamical time and resembles an isotropic structure. We also explore the effect of the uncertainties on the HST proper motions on the coherence of the VPOS as a function of time. We find that nine of the eleven classical dwarfs have reliable proper motions; for these nine, the VPOS also deteriorates in less than a dynamical time, indicating that the VPOS is not a dynamically stable structure. I will also briefly discuss the observational work that I have done during my thesis, including HI observations of lensed spiral galaxies to constrain CDM sub-structure.
- Publication:
-
American Astronomical Society Meeting Abstracts #229
- Pub Date:
- January 2017
- Bibcode:
- 2017AAS...22912307L