Chemical Cartography of the Sagittarius Stream with Gaia
The stellar stream connected to the Sagittarius (Sgr) dwarf galaxy is the most massive tidal stream that has been mapped in the Galaxy, and is the dominant contributor to the outer stellar halo of the Milky Way (MW). We present metallicity maps of the Sgr stream, using 34,240 red giant branch stars...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad187b |
| _version_ | 1797278917553291264 |
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| author | Emily C. Cunningham Jason A. S. Hunt Adrian M. Price-Whelan Kathryn V. Johnston Melissa K. Ness Yuxi (Lucy) Lu Ivanna Escala Ioana A. Stelea |
| author_facet | Emily C. Cunningham Jason A. S. Hunt Adrian M. Price-Whelan Kathryn V. Johnston Melissa K. Ness Yuxi (Lucy) Lu Ivanna Escala Ioana A. Stelea |
| author_sort | Emily C. Cunningham |
| collection | DOAJ |
| description | The stellar stream connected to the Sagittarius (Sgr) dwarf galaxy is the most massive tidal stream that has been mapped in the Galaxy, and is the dominant contributor to the outer stellar halo of the Milky Way (MW). We present metallicity maps of the Sgr stream, using 34,240 red giant branch stars with inferred metallicities from Gaia BP/RP spectra. This sample is larger than previous samples of Sgr stream members with chemical abundances by an order of magnitude. We measure metallicity gradients with respect to Sgr stream coordinates (Λ, B ), and highlight the gradient in metallicity with respect to stream latitude coordinate B , which has not been observed before. Including the core, we find ∇[M/H] = −2.48 ± 0.08 × 10 ^−2 dex deg ^−1 above the stream track ( B > B _0 , where B _0 = 1.5° is the latitude of the Sgr remnant) and ∇[M/H] = −2.02 ± 0.08 × 10 ^−2 dex deg ^−1 below the stream track ( B < B _0 ). By painting metallicity gradients onto a tailored N -body simulation of the Sgr stream, we find that the observed metallicities in the stream are consistent with an initial radial metallicity gradient in the Sgr dwarf galaxy of ∼−0.1 to −0.2 dex kpc ^−1 , well within the range of observed metallicity gradients in Local Group dwarf galaxies. Our results provide novel observational constraints for the internal structure of the dwarf galaxy progenitor of the Sgr stream. Leveraging new large data sets in conjunction with tailored simulations, we can connect the present-day properties of disrupted dwarfs in the MW to their initial conditions. |
| first_indexed | 2024-03-07T16:15:59Z |
| format | Article |
| id | doaj.art-88cd17b25ac3497ea0c88ac466f617a3 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-07T16:15:59Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-88cd17b25ac3497ea0c88ac466f617a32024-03-04T10:39:10ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196329510.3847/1538-4357/ad187bChemical Cartography of the Sagittarius Stream with GaiaEmily C. Cunningham0https://orcid.org/0000-0002-6993-0826Jason A. S. Hunt1https://orcid.org/0000-0001-8917-1532Adrian M. Price-Whelan2https://orcid.org/0000-0003-0872-7098Kathryn V. Johnston3https://orcid.org/0000-0001-6244-6727Melissa K. Ness4https://orcid.org/0000-0001-5082-6693Yuxi (Lucy) Lu5https://orcid.org/0000-0003-4769-3273Ivanna Escala6https://orcid.org/0000-0002-9933-9551Ioana A. Stelea7https://orcid.org/0000-0002-4110-8769Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY, 10027, USA ; e.cunningham@columbia.edu; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USACenter for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USA; School of Mathematics & Physics, University of Surrey , Guildford, GU2 7XH, UKCenter for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USADepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY, 10027, USA ; e.cunningham@columbia.eduDepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY, 10027, USA ; e.cunningham@columbia.edu; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USADepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY, 10027, USA ; e.cunningham@columbia.edu; Department of Astrophysics, American Museum of Natural History , 200 Central Park West, Manhattan, NY, USADepartment of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USA; The Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USADepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY, 10027, USA ; e.cunningham@columbia.edu; Department of Astronomy, University of Wisconsin - Madison , Madison, WI, USAThe stellar stream connected to the Sagittarius (Sgr) dwarf galaxy is the most massive tidal stream that has been mapped in the Galaxy, and is the dominant contributor to the outer stellar halo of the Milky Way (MW). We present metallicity maps of the Sgr stream, using 34,240 red giant branch stars with inferred metallicities from Gaia BP/RP spectra. This sample is larger than previous samples of Sgr stream members with chemical abundances by an order of magnitude. We measure metallicity gradients with respect to Sgr stream coordinates (Λ, B ), and highlight the gradient in metallicity with respect to stream latitude coordinate B , which has not been observed before. Including the core, we find ∇[M/H] = −2.48 ± 0.08 × 10 ^−2 dex deg ^−1 above the stream track ( B > B _0 , where B _0 = 1.5° is the latitude of the Sgr remnant) and ∇[M/H] = −2.02 ± 0.08 × 10 ^−2 dex deg ^−1 below the stream track ( B < B _0 ). By painting metallicity gradients onto a tailored N -body simulation of the Sgr stream, we find that the observed metallicities in the stream are consistent with an initial radial metallicity gradient in the Sgr dwarf galaxy of ∼−0.1 to −0.2 dex kpc ^−1 , well within the range of observed metallicity gradients in Local Group dwarf galaxies. Our results provide novel observational constraints for the internal structure of the dwarf galaxy progenitor of the Sgr stream. Leveraging new large data sets in conjunction with tailored simulations, we can connect the present-day properties of disrupted dwarfs in the MW to their initial conditions.https://doi.org/10.3847/1538-4357/ad187bMilky Way stellar haloChemical abundancesGalaxy chemical evolutionStellar streams |
| spellingShingle | Emily C. Cunningham Jason A. S. Hunt Adrian M. Price-Whelan Kathryn V. Johnston Melissa K. Ness Yuxi (Lucy) Lu Ivanna Escala Ioana A. Stelea Chemical Cartography of the Sagittarius Stream with Gaia The Astrophysical Journal Milky Way stellar halo Chemical abundances Galaxy chemical evolution Stellar streams |
| title | Chemical Cartography of the Sagittarius Stream with Gaia |
| title_full | Chemical Cartography of the Sagittarius Stream with Gaia |
| title_fullStr | Chemical Cartography of the Sagittarius Stream with Gaia |
| title_full_unstemmed | Chemical Cartography of the Sagittarius Stream with Gaia |
| title_short | Chemical Cartography of the Sagittarius Stream with Gaia |
| title_sort | chemical cartography of the sagittarius stream with gaia |
| topic | Milky Way stellar halo Chemical abundances Galaxy chemical evolution Stellar streams |
| url | https://doi.org/10.3847/1538-4357/ad187b |
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