Pristine dwarf galaxy survey - I. A detailed photometric and spectroscopic study of the very metal-poor Draco II satellite

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dc.contributor.authorLongeard, Nicolas
dc.contributor.authorMartin, Nicolas
dc.contributor.authorStarkenburg, Else
dc.contributor.authorIbata, Rodrigo A.
dc.contributor.authorCollins, Michelle L. M.
dc.contributor.authorGeha, Marla
dc.contributor.authorLaevens, Benjamin P. M.
dc.contributor.authorRich, R. Michael
dc.contributor.authorAguado, David S.
dc.contributor.authorArentsen, Anke
dc.contributor.authorCarlberg, Raymond G.
dc.contributor.authorCote, Patrick
dc.contributor.authorHill, Vanessa
dc.contributor.authorJablonka, Pascale
dc.contributor.authorGonzalez Hernandez, Jonay I.
dc.contributor.authorNavarro, Julio F.
dc.contributor.authorSanchez-Janssen, Ruben
dc.contributor.authorTolstoy, Eline
dc.contributor.authorVenn, Kim A.
dc.contributor.authorYouakim, Kris
dc.date.accessioned2025-01-23T21:21:35Z
dc.date.available2025-01-23T21:21:35Z
dc.date.issued2018
dc.description.abstractWe present a detailed study of the faint Milky Way satellite Draco II (Dra II) from deep CFHT/MegaCam broad-band g and i photometry and narrow-band metallicity-sensitive CaliK observations, along with follow-up Keck II/DEIMOS multi-object spectroscopy. Forward modelling of the deep photometry allows us to refine the structural and photometric properties of Dra II: the distribution of stars in colour-magnitude space implies Dra II is old (13.5 +/- 0.5 Gyr), very metal-poor, very faint (L-v = 180(-72)(+124) L-circle dot), and at a distance d = 21.5 +/- 0.4 kpc. The narrow-band, metallicity-sensitive Cal-IK Pristine photometry confirms this very low metallicity ([Fe/H] = -2.7 +/- 0.1 dex). Even though our study benefits from a doubling of the spectroscopic sample size compared to previous investigations, the velocity dispersion of the system is still only marginally resolved (sigma(vr) < 5.9 km s(-1) at the 95 per cent confidence level) and confirms that Dra II is a dynamically cold stellar system with a large recessional velocity (< v(r)> = -342.5(-1.2)(+1.1)km s(-)1). We further show that the spectroscopically confirmed members of Dra II have a mean proper motion of (mu(alpha)*, mu(delta)) = (1.26 +/- 0.27, 0.94 +/- 0.28) mas/yr in the Gaia DR2 data, which translates to an orbit with a pericentre and an apocentre of 21.3(-1.0)(+0.7) and 153.8(-34.7)(+56.7) kpc, respectively. Taken altogether, these properties favour the scenario of Dra II being a potentially disrupting dwarf galaxy. The low-significance extra-tidal features we map around the satellite tentatively support this scenario.
dc.fuente.origenWOS
dc.identifier.doi10.1093/mnras/sty1986
dc.identifier.eissn1365-2966
dc.identifier.issn0035-8711
dc.identifier.urihttps://doi.org/10.1093/mnras/sty1986
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/101232
dc.identifier.wosidWOS:000449614800092
dc.issue.numero2
dc.language.isoen
dc.pagina.final2627
dc.pagina.inicio2609
dc.revistaMonthly notices of the royal astronomical society
dc.rightsacceso restringido
dc.subjectgalaxies: dwarf
dc.subjectgalaxies: individual: Draco II
dc.subjectLocal Group
dc.titlePristine dwarf galaxy survey - I. A detailed photometric and spectroscopic study of the very metal-poor Draco II satellite
dc.typeartículo
dc.volumen480
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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