The Pristine Dwarf-Galaxy survey — III. Revealing the nature of the Milky Way globular cluster Sagittarius II. (arXiv:2005.05976v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Longeard_N/0/1/0/all/0/1">Nicolas Longeard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Martin_N/0/1/0/all/0/1">Nicolas Martin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ibata_R/0/1/0/all/0/1">Rodrigo Ibata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starkenburg_E/0/1/0/all/0/1">Else Starkenburg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jablonka_P/0/1/0/all/0/1">Pascale Jablonka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aguado_D/0/1/0/all/0/1">David S. Aguado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carlberg_R/0/1/0/all/0/1">Raymond G. Carlberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cote_P/0/1/0/all/0/1">Patrick Côté</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hernandez_J/0/1/0/all/0/1">Jonay I. González Hernández</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lucchesi_R/0/1/0/all/0/1">Romain Lucchesi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Malhan_K/0/1/0/all/0/1">Khyati Malhan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Navarro_J/0/1/0/all/0/1">Julio F. Navarro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_Janssen_R/0/1/0/all/0/1">Rubén Sánchez-Janssen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thomas_G/0/1/0/all/0/1">Guillaume F. Thomas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Venn_K/0/1/0/all/0/1">Kim Venn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McConnachie_A/0/1/0/all/0/1">Alan W. McConnachie</a>
We present a new spectroscopic study of the faint Milky Way satellite
Sagittarius II. Using multi-object spectroscopy from the Fibre Large Array
Multi Element Spectrograph, we supplement the dataset of Longeard et al. (2020)
with 47 newly observed stars, 19 of which are identified as members of the
satellite. These additional member stars are used to put tighter constraints on
the dynamics and the metallicity properties of the system. We find a low
velocity dispersion of SgrII v = 1.7 +/- 0.5 km s-1, in agreement with the
dispersion of Milky Way globular clusters of similar luminosity. We confirm the
very metal-poor nature of the satellite ([Fe/H]_SgrII = -2.23 +/- 0.07) and
find that the metallicity dispersion of Sgr II is not resolved, reaching only
0.20 at the 95% confidence limit. No star with a metallicity below -2.5 is
confidently detected. Therefore, despite the unusually large size of the system
(rh = 35.5 +1.4-1.2 pc), we conclude that Sgr II is an old and metal-poor
globular cluster of the Milky Way.
We present a new spectroscopic study of the faint Milky Way satellite
Sagittarius II. Using multi-object spectroscopy from the Fibre Large Array
Multi Element Spectrograph, we supplement the dataset of Longeard et al. (2020)
with 47 newly observed stars, 19 of which are identified as members of the
satellite. These additional member stars are used to put tighter constraints on
the dynamics and the metallicity properties of the system. We find a low
velocity dispersion of SgrII v = 1.7 +/- 0.5 km s-1, in agreement with the
dispersion of Milky Way globular clusters of similar luminosity. We confirm the
very metal-poor nature of the satellite ([Fe/H]_SgrII = -2.23 +/- 0.07) and
find that the metallicity dispersion of Sgr II is not resolved, reaching only
0.20 at the 95% confidence limit. No star with a metallicity below -2.5 is
confidently detected. Therefore, despite the unusually large size of the system
(rh = 35.5 +1.4-1.2 pc), we conclude that Sgr II is an old and metal-poor
globular cluster of the Milky Way.
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