Kinematics of the Tucana dwarf galaxy: an unusually dense dwarf in the Local Group

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1093/mnras/stz518
Auteur	Rechercher : Gregory, Alexandra l.; Rechercher : Collins, Michelle l. M.Identifiant ORCID : https://orcid.org/0000-0002-1693-3265; Rechercher : Read, Justin I.Identifiant ORCID : https://orcid.org/0000-0002-1164-9302; Rechercher : Irwin, Michael J.; Rechercher : Ibata, Rodrigo A.; Rechercher : Martin, Nicolas F.; Rechercher : McConnachie, Alan W.¹; Rechercher : Weisz, Daniel R.Identifiant ORCID : https://orcid.org/0000-0002-6442-6030
Affiliation	Conseil national de recherches Canada. Herzberg en astronomie et en astrophysique
Format	Texte, Article
Sujet	galaxies: dwarf; galaxies: evolution; galaxies: haloes; galaxies: kinematics and dynamics; Local Group
Résumé	We present new FLAMES+GIRAFFE spectroscopy of 36 member stars in the isolated Local Group dwarf spheroidal galaxy Tucana. We measure a systemic velocity for the system of vTuc=216.7⁺².⁹−₂.₈ km s⁻¹, and a velocity dispersion of σv,Tuc=14.4⁺².⁸−₂.₃ km s−¹. We also detect a rotation gradient of dvᵣ/dχ=7.6⁺⁴.²−₄.₃ km s−¹ kpc−¹, which reduces the systemic velocity to vTuc=215.2⁺².⁸−₂.₇ km s−¹ and the velocity dispersion to σv,Tuc=13.3⁺².⁷−₂.₃ km s−¹. We perform Jeans modelling of the density profile of Tucana, using the line-of-sight velocities of the member stars. We find that it favours a high central density consistent with ‘pristine’ subhaloes in Λ cold dark matter, and a massive dark matter halo (∼10¹⁰ M⊙) consistent with expectations from abundance matching. Tucana appears to be significantly more centrally dense than other isolated Local Group dwarfs, making it an ideal laboratory for testing dark matter models.
Date de publication	2019-02-20
Maison d’édition	Oxford
Dans	Monthly Notices of the Royal Astronomical Society 485, nº 2 : 2010–2025.
Langue	anglais
Publications évaluées par des pairs	Oui
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Identificateur de l’enregistrement	cbbdd6f1-606a-4097-87b8-569116382c0f
Enregistrement créé	2021-03-18
Enregistrement modifié	2021-03-18

Date de modification :: 2026-01-25