SIMBAD references

2020MNRAS.491..356L - Mon. Not. R. Astron. Soc., 491, 356-377 (2020/January-1)

The Pristine Dwarf-Galaxy survey - II. In-depth observational study of the faint Milky Way satellite Sagittarius II.

LONGEARD N., MARTIN N., STARKENBURG E., IBATA R.A., COLLINS M.L.M., LAEVENS B.P.M., MACKEY D., RICH R.M., AGUADO D.S., ARENTSEN A., JABLONKA P., GONZALEZ HERNANDEZ J.I., NAVARRO J.F. and SANCHEZ-JANSSEN R.

Abstract (from CDS):

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. 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 ± 0.5 Gyr) and metal poor. The CaHK photometry confirms the metal-poor nature of the satellite ([Fe/H] CaHK = -2.32 ± 0.04 dex) and suggests that Sgr II hosts more than one single stellar population (σ _[FeH]^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 ± 0.05 dex, σ _[Fe/H]^spectro = 0.10 ^{+0.06}_{-0.04} dex). The velocity dispersion of the system is found to be σ v = 2.7^{+1.3}_{-1.0} { km s^{-1}} after excluding two potential binary stars. Sgr II's metallicity and absolute magnitude (MV = -5.7 ± 0.1 mag) 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☉ L^{-1}_{☉ }). 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.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: dwarf - Local Group

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 46

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2021.04.13-12:41:11

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