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 Based on observations carried out at the Magellan/Clay telescope under program CN2018B-71.

Sandro Villanova, Lorenzo Monaco, Doug Geisler, Julia O'Connell, Dante Minniti, Paulina Assmann, Rodolfo Barbá

Resultado de la investigación: Article

1 Cita (Scopus)

Resumen

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 . 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.

Idioma originalEnglish
Número de artículo174
PublicaciónAstrophysical Journal
Volumen882
N.º2
DOI
EstadoPublished - 10 sep 2019

Huella dactilar

dwarf galaxies
globular clusters
clays
chemical composition
accretion
telescopes
orbits
clay
radial velocity
metallicity
retrograde orbits
galactic bulge
eccentrics
proper motion
velocity measurement
halos
wavelength
iron
orbitals
high resolution

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

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title = "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 Based on observations carried out at the Magellan/Clay telescope under program CN2018B-71.",
abstract = "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 . 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.",
author = "Sandro Villanova and Lorenzo Monaco and Doug Geisler and Julia O'Connell and Dante Minniti and Paulina Assmann and Rodolfo Barb{\'a}",
year = "2019",
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doi = "10.3847/1538-4357/ab3722",
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TY - JOUR

T1 - Detailed Chemical Composition and Orbit of the Newly Discovered Globular Cluster FSR 1758

T2 - Implications for the Accretion of the Sequoia Dwarf Galaxy onto the Milky Way Based on observations carried out at the Magellan/Clay telescope under program CN2018B-71.

AU - Villanova, Sandro

AU - Monaco, Lorenzo

AU - Geisler, Doug

AU - O'Connell, Julia

AU - Minniti, Dante

AU - Assmann, Paulina

AU - Barbá, Rodolfo

PY - 2019/9/10

Y1 - 2019/9/10

N2 - 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 . 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.

AB - 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 . 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.

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