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Constraining the Formation History of the Galactic Disk and Halo Systems through Kinematic Studies of Metal-Poor Stars

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posted on 2020-12-07, 00:00 authored by Sarah E. Dietz

The analyses presented in this work all fall under the umbrella term 'Galactic archaeology', the sub-field of astronomy dedicated to reconstructing the assembly and chemical-evolution history of the Galaxy. The following chapters chart a journey through the Milky Way, from the disk system to the stellar halo and the outskirts of the Galaxy, identifying stellar chemo-dynamical patterns that may shed light on the complex mechanisms involved in forming these components. In particular, I use metal-poor stars, and their close associates, carbon-enhanced metal-poor (CEMP) stars, throughout my analyses as tracer populations (or stellar 'fossils') to map features of interest. In the thick-disk, I identify two unusual CEMP populations, and describe their potential implications for the history of the disk system, potentially supporting a separable metal-weak thick-disk (MWTD) component. In the halo, I compare two CEMP-based methods for verifying the inner- and outer-halo separation, and cover the recent changes to our understanding of the halo following the release of high-precision astrometry from the Gaia satellite. At the outskirts of the halo, I present evidence of an asymmetric metallicity gradient within this region, and discuss its implications for the complex accretion history of the outer-halo component.

History

Date Modified

2021-01-12

Defense Date

2020-07-07

CIP Code

  • 40.0801

Research Director(s)

Vinicius M. Placco

Committee Members

Peter Garnavich Malgorzata Dobrowolska J. Christopher Howk

Degree

  • Doctor of Philosophy

Degree Level

  • Doctoral Dissertation

Alternate Identifier

1230150392

Library Record

5963352

OCLC Number

1230150392

Program Name

  • Physics

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