A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence
We continue our series of papers on phase-space distributions of stars in the Milky Way based on photometrically derived metallicities and Gaia astrometry, with a focus on the halo−disk interface in the local volume. To exploit various photometric databases, we develop a method of empirically calibr...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acd5cb |
| _version_ | 1797698283167023104 |
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| author | Deokkeun An Timothy C. Beers Young Sun Lee Thomas Masseron |
| author_facet | Deokkeun An Timothy C. Beers Young Sun Lee Thomas Masseron |
| author_sort | Deokkeun An |
| collection | DOAJ |
| description | We continue our series of papers on phase-space distributions of stars in the Milky Way based on photometrically derived metallicities and Gaia astrometry, with a focus on the halo−disk interface in the local volume. To exploit various photometric databases, we develop a method of empirically calibrating synthetic stellar spectra based on a comparison with observations of stellar sequences and individual stars in the Sloan Digital Sky Survey, the SkyMapper Sky Survey, and the Pan-STARRS1 surveys, overcoming band-specific corrections employed in our previous work. In addition, photometric zero-point corrections are derived to provide an internally consistent photometric system with a spatially uniform metallicity zero-point. Using our phase-space diagrams, we find a remarkably narrow sequence in the rotational velocity ( v _ϕ ) versus metallicity ([Fe/H]) space for a sample of high proper-motion stars (>25 mas yr ^−1 ), which runs along Gaia Sausage/Enceladus (GSE) and the Splash substructures and is linked to the disk, spanning nearly 2 dex in [Fe/H]. Notably, a rapid increase of v _ϕ from a nearly zero net rotation to ∼180 km s ^−1 in a narrow metallicity interval (−0.6 ≲ [Fe/H] ≲ −0.4) suggests that some of these stars emerged quickly on a short gas-depletion timescale. Through measurements of a scale height and length, we argue that these stars are distinct from those heated dynamically by mergers. This chain of high proper-motion stars provides additional support for recent discoveries suggesting that a starburst took place when the young Milky Way encountered the gas-rich GSE progenitor, which eventually led to the settling of metal-enriched gas onto the disk. |
| first_indexed | 2024-03-12T03:51:55Z |
| format | Article |
| id | doaj.art-c58ce7d0bc714805803c5cbb01432abb |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:51:55Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-c58ce7d0bc714805803c5cbb01432abb2023-09-03T12:17:44ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195216610.3847/1538-4357/acd5cbA Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst SequenceDeokkeun An0https://orcid.org/0000-0002-8072-7511Timothy C. Beers1https://orcid.org/0000-0003-4573-6233Young Sun Lee2https://orcid.org/0000-0001-5297-4518Thomas Masseron3https://orcid.org/0000-0002-6939-0831Department of Science Education, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Republic of Korea ; deokkeun@ewha.ac.krDepartment of Physics and Astronomy and JINA Center for the Evolution of the Elements, University of Notre Dame , Notre Dame, IN 46556, USADepartment of Physics and Astronomy and JINA Center for the Evolution of the Elements, University of Notre Dame , Notre Dame, IN 46556, USA; Department of Astronomy and Space Science, Chungnam National University , Daejeon 34134, Republic of KoreaInstituto de Astrofísica de Canarias (IAC) , E-38200 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206 La Laguna, Tenerife, SpainWe continue our series of papers on phase-space distributions of stars in the Milky Way based on photometrically derived metallicities and Gaia astrometry, with a focus on the halo−disk interface in the local volume. To exploit various photometric databases, we develop a method of empirically calibrating synthetic stellar spectra based on a comparison with observations of stellar sequences and individual stars in the Sloan Digital Sky Survey, the SkyMapper Sky Survey, and the Pan-STARRS1 surveys, overcoming band-specific corrections employed in our previous work. In addition, photometric zero-point corrections are derived to provide an internally consistent photometric system with a spatially uniform metallicity zero-point. Using our phase-space diagrams, we find a remarkably narrow sequence in the rotational velocity ( v _ϕ ) versus metallicity ([Fe/H]) space for a sample of high proper-motion stars (>25 mas yr ^−1 ), which runs along Gaia Sausage/Enceladus (GSE) and the Splash substructures and is linked to the disk, spanning nearly 2 dex in [Fe/H]. Notably, a rapid increase of v _ϕ from a nearly zero net rotation to ∼180 km s ^−1 in a narrow metallicity interval (−0.6 ≲ [Fe/H] ≲ −0.4) suggests that some of these stars emerged quickly on a short gas-depletion timescale. Through measurements of a scale height and length, we argue that these stars are distinct from those heated dynamically by mergers. This chain of high proper-motion stars provides additional support for recent discoveries suggesting that a starburst took place when the young Milky Way encountered the gas-rich GSE progenitor, which eventually led to the settling of metal-enriched gas onto the disk.https://doi.org/10.3847/1538-4357/acd5cbMilky Way GalaxyMilky Way stellar haloMilky Way dynamicsMilky Way formationMilky Way evolutionStellar abundances |
| spellingShingle | Deokkeun An Timothy C. Beers Young Sun Lee Thomas Masseron A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence The Astrophysical Journal Milky Way Galaxy Milky Way stellar halo Milky Way dynamics Milky Way formation Milky Way evolution Stellar abundances |
| title | A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence |
| title_full | A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence |
| title_fullStr | A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence |
| title_full_unstemmed | A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence |
| title_short | A Blueprint for the Milky Way’s Stellar Populations. IV. A String of Pearls—the Galactic Starburst Sequence |
| title_sort | blueprint for the milky way s stellar populations iv a string of pearls the galactic starburst sequence |
| topic | Milky Way Galaxy Milky Way stellar halo Milky Way dynamics Milky Way formation Milky Way evolution Stellar abundances |
| url | https://doi.org/10.3847/1538-4357/acd5cb |
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