Table · dataset · 2023
Sagittarius II study with the Pristine survey
Listed in IVOA Registry (Virtual Observatory)
We present an extensive study of the Sagittarius II (Sgr II) stellar system using MegaCam g and i photometry, narrow-band, metallicity-sensitive calcium H&K doublet photometry and Keck II/DEIMOS multiobject spectroscopy.
Description
We derive and refine the Sgr II structural and stellar properties inferred at the time of its discovery. The colour-magnitude diagram implies Sgr II is old (12.0+/-0.5Gyr) and metal poor.
The CaHK photometry confirms the metal-poor nature of the satellite ([Fe/H]_CaHK_=-2.32+/-0.04dex) and suggests that Sgr II hosts more than one single stellar population ({sigma}_[Fe/H]_^CaHK^=0.11^+0.05^_-0.03_dex). Using the Ca infrared triplet measured from our highest signal-to-noise spectra, we confirm the metallicity and dispersion inferred from the Pristine photometric metallicities ([Fe/H]_spectro_=-2.23+/-0.05dex, {sigma}_[Fe/H]_^spectro^=0.10^+0.06^_-0.04_dex).
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The velocity dispersion of the system is found to be {sigma}_v_=2.7^+1.3^_-1.0_km/s after excluding two potential binary stars. Sgr II's metallicity and absolute magnitude (M_V_=-5.7+/-0.1mag) place the system on the luminosity-metallicity relation of the Milky Way dwarf galaxies despite its small size. The low but resolved metallicity and velocity dispersions paint the picture of a slightly dark-matter-dominated satellite (M/L=23.0^+32.8^_-23.0_M_{sun}_/L_{sun}_).
Furthermore, using the Gaia Data Release 2, we constrain the orbit of the satellite and find an apocentre of 118.4^+28.4^_-23.7_kpc and a pericentre of 54.8^+3.3^_-6.1_kpc. The orbit of Sgr II is consistent with the trailing arm of the Sgr stream and indicates that it is possibly a satellite of the Sgr dSph that was tidally stripped from the dwarf's influence.
Links
Where it is published
- Reference page cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/491/356 ↗
landing page · from IVOA Registry
Documentation and papers
- ADS 2020MNRAS.491..356L ui.adsabs.harvard.edu/abs/2020MNRAS.491..356L ↗
publication · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/cds.vizier/j/mnras/491/356 ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- Optical
- From keywords
- Astronomy & Astrophysics
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://cds.vizier/j/mnras/491/356 | 12 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:optical | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| license_text | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |