The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake
The infall of the Large Magellanic Cloud (LMC) into the Milky Way’s halo impacts the distribution of stars and dark matter (DM) in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly dist...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/adbf08 |
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| author | Manuel Cavieres Julio Chanamé Camila Navarrete Yasna Ordenes-Briceño Nicolás Garavito-Camargo Gurtina Besla Maren Hempel A. Katherina Vivas Facundo Gómez |
| author_facet | Manuel Cavieres Julio Chanamé Camila Navarrete Yasna Ordenes-Briceño Nicolás Garavito-Camargo Gurtina Besla Maren Hempel A. Katherina Vivas Facundo Gómez |
| author_sort | Manuel Cavieres |
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| description | The infall of the Large Magellanic Cloud (LMC) into the Milky Way’s halo impacts the distribution of stars and dark matter (DM) in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly distinguish between different DM models. N -body simulations predict a localized overdensity trailing the LMC’s orbit both in baryonic and DM, known as the wake. We collected wide-field, deep near-infrared, and optical photometry using VIRCAM and DECam across four fields along the expected wake, covering the sky region expected to span most of its predicted density contrast. We identify over 400 stars comprising two different tracers, near main-sequence turnoff stars and red giants, which map the halo between 60 and 100 kpc, deriving stellar halo densities as a function of sky position and Galactocentric radius. We detect (1) a break in the halo radial density profile at 70 kpc not seen in northern halo studies and (2) a clear halo overdensity starting also at 70 kpc, with density contrast increasing steadily toward the expected current location of the wake. If this overdensity is the LMC wake, its peak density contrast is as pronounced as the most massive LMC model considered. Contamination from unidentified substructures may bias our wake detections, so wider-area surveys with similar depth are needed for confirmation. |
| format | Article |
| id | doaj-art-48a73d7e3d22489dbe4879507d89d607 |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-48a73d7e3d22489dbe4879507d89d6072025-08-20T02:08:27ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198318310.3847/1538-4357/adbf08The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction WakeManuel Cavieres0https://orcid.org/0009-0002-2978-8383Julio Chanamé1https://orcid.org/0000-0003-2481-4546Camila Navarrete2https://orcid.org/0000-0002-4777-9934Yasna Ordenes-Briceño3https://orcid.org/0000-0001-7966-7606Nicolás Garavito-Camargo4https://orcid.org/0000-0001-7107-1744Gurtina Besla5https://orcid.org/0000-0003-0715-2173Maren Hempel6https://orcid.org/0000-0002-2982-8712A. Katherina Vivas7https://orcid.org/0000-0003-4341-6172Facundo Gómez8https://orcid.org/0000-0002-1947-333XInstituto de Astrofísica, Pontificia Universidad Católica de Chile , Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile ; mncavieres@uc.clInstituto de Astrofísica, Pontificia Universidad Católica de Chile , Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile ; mncavieres@uc.clObservatoire de la Côte d’Azur , Boulevard de l’Observatoire, 06304 Nice, FranceInstituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales , Av. Ejército Libertador 441, Santiago, ChileCenter for Computational Astrophysics, Flatiron Institute , 162 5th Ave, New York, NY 10010, USAUniversity of Arizona , 933 N. Cherry Ave, Tucson, AZ 85721, USAUniversidad Andrés Bello , Fernandez Concha 700, Las Condes, Santiago, Chile; Max-Planck Institute for Astrophysics , Königstuhl 17, 69117 Heidelberg, GermanyCerro Tololo Inter-American Observatory/NSF’s NOIRLab , Casilla 603, La Serena, ChileUniversidad de la Serena , Avenida Cisternas 1200, La Serena, ChileThe infall of the Large Magellanic Cloud (LMC) into the Milky Way’s halo impacts the distribution of stars and dark matter (DM) in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly distinguish between different DM models. N -body simulations predict a localized overdensity trailing the LMC’s orbit both in baryonic and DM, known as the wake. We collected wide-field, deep near-infrared, and optical photometry using VIRCAM and DECam across four fields along the expected wake, covering the sky region expected to span most of its predicted density contrast. We identify over 400 stars comprising two different tracers, near main-sequence turnoff stars and red giants, which map the halo between 60 and 100 kpc, deriving stellar halo densities as a function of sky position and Galactocentric radius. We detect (1) a break in the halo radial density profile at 70 kpc not seen in northern halo studies and (2) a clear halo overdensity starting also at 70 kpc, with density contrast increasing steadily toward the expected current location of the wake. If this overdensity is the LMC wake, its peak density contrast is as pronounced as the most massive LMC model considered. Contamination from unidentified substructures may bias our wake detections, so wider-area surveys with similar depth are needed for confirmation.https://doi.org/10.3847/1538-4357/adbf08Magellanic CloudsMilky Way dark matter haloMilky Way stellar haloDark matterLarge Magellanic CloudSmall Magellanic Cloud |
| spellingShingle | Manuel Cavieres Julio Chanamé Camila Navarrete Yasna Ordenes-Briceño Nicolás Garavito-Camargo Gurtina Besla Maren Hempel A. Katherina Vivas Facundo Gómez The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake The Astrophysical Journal Magellanic Clouds Milky Way dark matter halo Milky Way stellar halo Dark matter Large Magellanic Cloud Small Magellanic Cloud |
| title | The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake |
| title_full | The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake |
| title_fullStr | The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake |
| title_full_unstemmed | The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake |
| title_short | The Distant Milky Way Halo from the Southern Hemisphere: Characterization of the LMC-induced Dynamical Friction Wake |
| title_sort | distant milky way halo from the southern hemisphere characterization of the lmc induced dynamical friction wake |
| topic | Magellanic Clouds Milky Way dark matter halo Milky Way stellar halo Dark matter Large Magellanic Cloud Small Magellanic Cloud |
| url | https://doi.org/10.3847/1538-4357/adbf08 |
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