SIMBAD references

2019ApJ...882..174V - Astrophys. J., 882, 174-174 (2019/September-2)

Detailed chemical composition and orbit of the newly discovered globular cluster FSR 1758: implications for the accretion of the Sequoia dwarf galaxy onto the Milky Way.

VILLANOVA S., MONACO L., GEISLER D., O'CONNELL J., MINNITI D., ASSMANN P. and BARBA R.

Abstract (from CDS):

We present detailed chemical abundances, radial velocity, and orbital parameters for FSR 1758, a recently discovered massive cluster in the direction of the Galactic bulge. High-resolution (R ∼ 42,000) spectra were obtained for nine members using the Magellan/Clay telescope instrumented with the MIKE echelle spectrogragh in the wavelength range of ∼4900-8700 Å. Cluster membership was determined using Gaia DR2 proper motions and confirmed with our radial velocity measurements. We find a metallicity of [Fe/H] = -1.58 ± 0.03, consistent with previous photometric estimates, and no significant iron spread. While other studies have suggested that this massive object could be the remnant of a captured dwarf galaxy, our results are consistent with a globular cluster (GC) nature, given its lack of any intrinsic metallicity spread and the Na-O anticorrelation similar to those of other GC. In addition, the small velocity dispersion of 4.9 ± 1.2 km s–1 we find is that typical of a GC. We also confirm a retrograde orbit that appears to be highly eccentric suggesting it is a halo interloper currently in the bulge. We support the hypothesis that FSR 1758 was part of a disrupted dwarf galaxy named Sequoia.

Abstract Copyright: © 2019. The American Astronomical Society. All rights reserved.

Journal keyword(s): Globular star clusters

Simbad objects: 18

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