The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way
In the first several hundred million years after the Big Bang, the first stars and galaxies transformed the Universe. These ancient systems launched the creation of every galaxy we see today, including the Milky Way. Ever since, for the last 13 billion years, the Milky Way has grown through galaxy m...
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| Format: | Thesis |
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Massachusetts Institute of Technology
2023
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| Online Access: | https://hdl.handle.net/1721.1/152576 |
| _version_ | 1826193777188929536 |
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| author | Brauer, Kaley |
| author2 | Frebel, Anna |
| author_facet | Frebel, Anna Brauer, Kaley |
| author_sort | Brauer, Kaley |
| collection | MIT |
| description | In the first several hundred million years after the Big Bang, the first stars and galaxies transformed the Universe. These ancient systems launched the creation of every galaxy we see today, including the Milky Way. Ever since, for the last 13 billion years, the Milky Way has grown through galaxy mergers. Several of these mergers were with other similarly-sized galaxies and possibly a hundred of these mergers were with small dwarf galaxies. The smallest dwarf galaxies accreted by the Milky Way, the ultra-faint dwarfs (UFDs), are relics of the first galaxies in the Universe and provide important insight into early galaxy formation and chemical enrichment. Currently, though, accreted UFDs are poorly understood and we lack ways to identify stars that accreted from UFDs. By utilizing a simulation suite of 35 Milky Way-mass galaxies forming, I find that chemical tagging with r-process elements and clustering in kinematic phase space can help us identify stars that accreted together from these dwarf galaxies. Kinematic clustering only identifies recently accreted UFDs, so we recommend chemical tagging as the more robust method to identify these stars. I also present an analytic model of collapsar enrichment that can self-consistently explain the observed scatter in r-process chemical elements of old stars. I am expanding on these studies with highly-resolved hydrodynamic simulations of the earliest dwarf galaxies, the Aeos simulations. The methodology and initial results for these simulations are also presented. |
| first_indexed | 2024-09-23T09:44:44Z |
| format | Thesis |
| id | mit-1721.1/152576 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T09:44:44Z |
| publishDate | 2023 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1525762023-11-01T03:54:27Z The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way Brauer, Kaley Frebel, Anna Massachusetts Institute of Technology. Department of Physics In the first several hundred million years after the Big Bang, the first stars and galaxies transformed the Universe. These ancient systems launched the creation of every galaxy we see today, including the Milky Way. Ever since, for the last 13 billion years, the Milky Way has grown through galaxy mergers. Several of these mergers were with other similarly-sized galaxies and possibly a hundred of these mergers were with small dwarf galaxies. The smallest dwarf galaxies accreted by the Milky Way, the ultra-faint dwarfs (UFDs), are relics of the first galaxies in the Universe and provide important insight into early galaxy formation and chemical enrichment. Currently, though, accreted UFDs are poorly understood and we lack ways to identify stars that accreted from UFDs. By utilizing a simulation suite of 35 Milky Way-mass galaxies forming, I find that chemical tagging with r-process elements and clustering in kinematic phase space can help us identify stars that accreted together from these dwarf galaxies. Kinematic clustering only identifies recently accreted UFDs, so we recommend chemical tagging as the more robust method to identify these stars. I also present an analytic model of collapsar enrichment that can self-consistently explain the observed scatter in r-process chemical elements of old stars. I am expanding on these studies with highly-resolved hydrodynamic simulations of the earliest dwarf galaxies, the Aeos simulations. The methodology and initial results for these simulations are also presented. Ph.D. 2023-10-30T20:04:10Z 2023-10-30T20:04:10Z 2023-06 2023-10-25T17:59:26.396Z Thesis https://hdl.handle.net/1721.1/152576 0000-0002-8810-858X In Copyright - Educational Use Permitted Copyright retained by author(s) https://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology |
| spellingShingle | Brauer, Kaley The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title | The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title_full | The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title_fullStr | The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title_full_unstemmed | The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title_short | The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way |
| title_sort | legacy of the first galaxies exploring ancient stars in the milky way |
| url | https://hdl.handle.net/1721.1/152576 |
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