HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

The pristine dwarf-galaxy survey – III. Revealing the nature of the Milky Way globular cluster Sagittarius II

Abstract : 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 σSgrIIv=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] SgrIIspectro=−2.23±0.07 ) and find that the metallicity dispersion of Sgr II is not resolved, reaching only 0.20 at the 95 per cent confidence limit. No star with a metallicity below -2.5 is confidently detected. Therefore, despite the unusually large size of the system (r h=35.5+1.4−1.2 pc), we conclude that Sgr II is an old and metal-poor globular cluster of the Milky Way.
Document type :
Journal articles
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-03176198
Contributor : Olivier Hauss Connect in order to contact the contributor
Submitted on : Monday, March 22, 2021 - 11:08:04 AM
Last modification on : Friday, April 1, 2022 - 3:44:05 AM

Links full text

Identifiers

Collections

Citation

Nicolas Longeard, Nicolas Martin, Rodrigo Ibata, Else Starkenburg, Pascale Jablonka, et al.. The pristine dwarf-galaxy survey – III. Revealing the nature of the Milky Way globular cluster Sagittarius II. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2021, 503 (2), pp.2754-2762. ⟨10.1093/mnras/stab604⟩. ⟨hal-03176198⟩

Share

Metrics

Record views

23