The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations
In the Λ-Cold Dark Matter model of the universe, galaxies form in part through accreting satellite systems. Previous works have built an understanding of the signatures of these processes contained within galactic stellar halos. This work revisits that picture using seven Milky Way–like galaxies in...
| 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/acae87 |
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| author | Danny Horta Emily C. Cunningham Robyn E. Sanderson Kathryn V. Johnston Nondh Panithanpaisal Arpit Arora Lina Necib Andrew Wetzel Jeremy Bailin Claude-André Faucher-Giguère |
| author_facet | Danny Horta Emily C. Cunningham Robyn E. Sanderson Kathryn V. Johnston Nondh Panithanpaisal Arpit Arora Lina Necib Andrew Wetzel Jeremy Bailin Claude-André Faucher-Giguère |
| author_sort | Danny Horta |
| collection | DOAJ |
| description | In the Λ-Cold Dark Matter model of the universe, galaxies form in part through accreting satellite systems. Previous works have built an understanding of the signatures of these processes contained within galactic stellar halos. This work revisits that picture using seven Milky Way–like galaxies in the Latte suite of FIRE-2 cosmological simulations. The resolution of these simulations allows a comparison of contributions from satellites above M _* ≳ 10 × ^7 M _⊙ , enabling the analysis of observable properties for disrupted satellites in a fully self-consistent and cosmological context. Our results show that the time of accretion and the stellar mass of an accreted satellite are fundamental parameters that in partnership dictate the resulting spatial distribution, orbital energy, and [ α /Fe]-[Fe/H] compositions of the stellar debris of such mergers at present day. These parameters also govern the resulting dynamical state of an accreted galaxy at z = 0, leading to the expectation that the inner regions of the stellar halo ( R _GC ≲ 30 kpc) should contain fully phase-mixed debris from both lower- and higher-mass satellites. In addition, we find that a significant fraction of the lower-mass satellites accreted at early times deposit debris in the outer halo ( R _GC > 50 kpc) that are not fully phased-mixed, indicating that they could be identified in kinematic surveys. Our results suggest that, as future surveys become increasingly able to map the outer halo of our Galaxy, they may reveal the remnants of long-dead dwarf galaxies whose counterparts are too faint to be seen in situ in higher-redshift surveys. |
| first_indexed | 2024-03-12T04:34:10Z |
| format | Article |
| id | doaj.art-c06db9bff245475796a2fae6c8e7fd16 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:34:10Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-c06db9bff245475796a2fae6c8e7fd162023-09-03T09:58:18ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01943215810.3847/1538-4357/acae87The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological SimulationsDanny Horta0https://orcid.org/0000-0003-1856-2151Emily C. Cunningham1https://orcid.org/0000-0002-6993-0826Robyn E. Sanderson2https://orcid.org/0000-0003-3939-3297Kathryn V. Johnston3https://orcid.org/0000-0001-6244-6727Nondh Panithanpaisal4https://orcid.org/0000-0001-5214-8822Arpit Arora5https://orcid.org/0000-0002-8354-7356Lina Necib6https://orcid.org/0000-0003-2806-1414Andrew Wetzel7https://orcid.org/0000-0003-0603-8942Jeremy Bailin8https://orcid.org/0000-0001-6380-010XClaude-André Faucher-Giguère9https://orcid.org/0000-0002-4900-6628Center for Computational Astrophysics , Flatiron Institute, 162 5th Ave., New York, NY 10010, USA ; dhortadarrington@flatironinstitute.org; Astrophysics Research Institute , Brownlow Hill, Liverpool, L3 5RF, UKCenter for Computational Astrophysics , Flatiron Institute, 162 5th Ave., New York, NY 10010, USA ; dhortadarrington@flatironinstitute.org; Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USACenter for Computational Astrophysics , Flatiron Institute, 162 5th Ave., New York, NY 10010, USA ; dhortadarrington@flatironinstitute.org; Department of Physics & Astronomy, University of Pennsylvania , 209 S 33rd St., Philadelphia, PA 19104, USACenter for Computational Astrophysics , Flatiron Institute, 162 5th Ave., New York, NY 10010, USA ; dhortadarrington@flatironinstitute.org; Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USADepartment of Physics & Astronomy, University of Pennsylvania , 209 S 33rd St., Philadelphia, PA 19104, USADepartment of Physics & Astronomy, University of Pennsylvania , 209 S 33rd St., Philadelphia, PA 19104, USAThe NSF AI Institute for Artificial Intelligence and Fundamental Interactions , USA; Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , 77 Massachusetts Ave, Cambridge MA 02139, USADepartment of Physics and Astronomy, University of California , Davis, CA 95616, USADepartment of Physics and Astronomy, University of Alabama , Tuscaloosa, AL 35487, USADepartment of Physics and Astronomy and CIERA, Northwestern University , 1800 Sherman Avenue, Evanston, IL 60201, USAIn the Λ-Cold Dark Matter model of the universe, galaxies form in part through accreting satellite systems. Previous works have built an understanding of the signatures of these processes contained within galactic stellar halos. This work revisits that picture using seven Milky Way–like galaxies in the Latte suite of FIRE-2 cosmological simulations. The resolution of these simulations allows a comparison of contributions from satellites above M _* ≳ 10 × ^7 M _⊙ , enabling the analysis of observable properties for disrupted satellites in a fully self-consistent and cosmological context. Our results show that the time of accretion and the stellar mass of an accreted satellite are fundamental parameters that in partnership dictate the resulting spatial distribution, orbital energy, and [ α /Fe]-[Fe/H] compositions of the stellar debris of such mergers at present day. These parameters also govern the resulting dynamical state of an accreted galaxy at z = 0, leading to the expectation that the inner regions of the stellar halo ( R _GC ≲ 30 kpc) should contain fully phase-mixed debris from both lower- and higher-mass satellites. In addition, we find that a significant fraction of the lower-mass satellites accreted at early times deposit debris in the outer halo ( R _GC > 50 kpc) that are not fully phased-mixed, indicating that they could be identified in kinematic surveys. Our results suggest that, as future surveys become increasingly able to map the outer halo of our Galaxy, they may reveal the remnants of long-dead dwarf galaxies whose counterparts are too faint to be seen in situ in higher-redshift surveys.https://doi.org/10.3847/1538-4357/acae87Galaxy formationMilky Way GalaxyMilky Way stellar haloMilky Way dynamics |
| spellingShingle | Danny Horta Emily C. Cunningham Robyn E. Sanderson Kathryn V. Johnston Nondh Panithanpaisal Arpit Arora Lina Necib Andrew Wetzel Jeremy Bailin Claude-André Faucher-Giguère The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations The Astrophysical Journal Galaxy formation Milky Way Galaxy Milky Way stellar halo Milky Way dynamics |
| title | The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations |
| title_full | The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations |
| title_fullStr | The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations |
| title_full_unstemmed | The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations |
| title_short | The Observable Properties of Galaxy Accretion Events in Milky Way–like Galaxies in the FIRE-2 Cosmological Simulations |
| title_sort | observable properties of galaxy accretion events in milky way like galaxies in the fire 2 cosmological simulations |
| topic | Galaxy formation Milky Way Galaxy Milky Way stellar halo Milky Way dynamics |
| url | https://doi.org/10.3847/1538-4357/acae87 |
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