The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with HST

Zoccali, M.; Renzini, A.; Ortolani, S.; Bica, E.; Barbuy, B.

doi:10.1007/978-94-010-0393-3_20

Cited by 3 publications

(1 citation statement)

References 31 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this paper, we present a chemical analysis for NGC 6553, which is a metal-rich Bulge GC with a metallicity of [𝐹𝑒/𝐻] = −0.18, located in the constellation Sagittarius at 2.2 Kpc from the Galactic Center (𝑙 = 5.25 • , 𝑏 = −3.02 • ) and at 6.0 Kpc from the Sun (Harris 2010). This cluster have an age of ∼ 13 Gyr (Zoccali et al 2002), a mass of 2.35 ± 0.19 × 10 5 𝑀 (Baumgardt & Hilker 2018), an excess color of 𝐸 (𝐵 − 𝑉) = 0.63 and an absolute visual magnitude of 𝑀 𝑉 = −7.77 (Harris 2010).…”

Section: Introductionmentioning

confidence: 99%

Chemical analysis of the Bulge Globular Cluster NGC 6553

Montecinos,

Villanova,

Muňoz

et al. 2021

Preprint

View full text Add to dashboard Cite

Globular Clusters are among the oldest objects in the Galaxy, thus their researchers are key to understanding the processes of evolution and formation that the galaxy has experienced in early stages. Spectroscopic studies allow us to carry out detailed analyzes on the chemical composition of Globular Clusters. The aim of our research is to perform a detailed analysis of chemical abundances to a sample of stars of the Bulge Globular Cluster NGC 6553, in order to determine chemical patterns that allow us to appreciate the phenomenon of Multiple Population in one of the most metal-rich Globular Clusters in the Galaxy. This analysis is being carried out with data obtained by FLAMES/GIRAFFE spectrograph, VVV Survey and DR2 of Gaia Mission. We analyzed 20 Red Horizontal Branch Stars, being the first extensive spectroscopic abundance analysis for this cluster and measured 8 chemical elements (O, Na, Mg, Si, Ca, Ti, Cr and Ni), deriving a mean iron content of [𝐹𝑒/𝐻] = −0.10 ± 0.01 and a mean of [𝛼/𝐹𝑒] = 0.21 ± 0.02, considering Mg, Si, Ca and Ti (errors on the mean). We found a significant spread in the content of Na but a small or negligible in O. We did not find an intrinsic variation in the content of 𝛼 and iron-peak elements, showing a good agreement with the trend of the Bulge field stars, suggesting a similar origin and evolution.

show abstract

Section: Introductionmentioning

confidence: 99%

Chemical analysis of the Bulge Globular Cluster NGC 6553

Montecinos,

Villanova,

Muňoz

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

Inspection of 19 globular cluster candidates in the Galactic bulge with the VVV survey

Garro

Minniti

Gómez

et al. 2022

A&A

View full text Add to dashboard Cite

Context. The census of the globular clusters (GCs) in the Milky Way (MW) is still a work in progress. The advent of new deep surveys has made it possible to discover many new star clusters both in the Galactic disk and bulge, but many of these new candidates have not yet been studied in detail, leaving a veil on their true physical nature. Aims. We explore the nature of 19 new GC candidates in the Galactic bulge by analysing their colour-magnitude diagrams (CMDs) in the near-infrared (NIR) using the VISTA Variables in the Via Láctea Survey (VVV) database. We estimate their main astrophysical parameters: reddening and extinction, distance, total luminosity, mean cluster proper motions (PMs), metallicity, and age. Methods. We obtain the cluster catalogues including the likely cluster members by applying a decontamination procedure on the observed CMDs based on the vector PM diagrams from VIRAC2. We adopt NIR reddening maps in order to calculate the reddening and extinction for each cluster, and then estimate the distance moduli and heliocentric distances. Metallicities and ages are evaluated by fitting theoretical stellar isochrones. We also calculate their luminosities in comparison with known Galactic GCs. Results. We estimate a wide reddening range of 0.25 E(J − K s ) 2.0 mag and extinction 0.11 A K s 0.86 mag for the sample clusters, as expected in the bulge regions. The range of heliocentric distances is 6.8 D 11.4 kpc. This allows us to place these clusters between 0.56 and 3.25 kpc from the Galactic centre, assuming R = 8.2 kpc. Also, their PMs are kinematically similar to the typical motion of the Galactic bulge, apart from VVV-CL160, which shows different PMs. We also derive their metallicities and ages, finding −1.40 [Fe/H] 0.0 dex and t ≈ 8 − 13 Gyr respectively. The luminosities are calculated both in K s − and V−bands, recovering −3.4 M V −7.5. We also examine the possible RR Lyrae members found in the cluster fields. Conclusions. Based on their positions, kinematics, metallicities, and ages, and comparing our results with the literature, we conclude that nine candidates are real GCs, seven need more observations to be fully confirmed as GCs, and three candidates are discarded as GCs and appear to be younger open clusters.

show abstract

Chemical analysis of the bulge globular cluster NGC 6553

Montecinos

Villanova

Muñoz

et al. 2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Globular Clusters are among the oldest objects in the Galaxy, thus their researchers are key to understanding the processes of evolution and formation that the galaxy has experienced in early stages. Spectroscopic studies allow us to carry out detailed analyzes on the chemical composition of Globular Clusters. The aim of our research is to perform a detailed analysis of chemical abundances to a sample of stars of the Bulge Globular Cluster NGC 6553, in order to determine chemical patterns that allow us to appreciate the phenomenon of Multiple Population in one of the most metal-rich Globular Clusters in the Galaxy. This analysis is being carried out with data obtained by FLAMES/GIRAFFE spectrograph, VVV Survey and DR2 of Gaia Mission. We analyzed 20 Red Horizontal Branch Stars, being the first extensive spectroscopic abundance analysis for this cluster and measured 8 chemical elements (O, Na, Mg, Si, Ca, Ti, Cr and Ni), deriving a mean iron content of [Fe/H] = −0.10 ± 0.01 and a mean of [α/Fe] = 0.21 ± 0.02, considering Mg, Si, Ca and Ti (errors on the mean). We found a significant spread in the content of Na but a small or negligible in O. We did not find an intrinsic variation in the content of α and iron-peak elements, showing a good agreement with the trend of the Bulge field stars, suggesting a similar origin and evolution.

show abstract

The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with HST

Cited by 3 publications

References 31 publications

Chemical analysis of the Bulge Globular Cluster NGC 6553

Chemical analysis of the Bulge Globular Cluster NGC 6553

Inspection of 19 globular cluster candidates in the Galactic bulge with the VVV survey

Chemical analysis of the bulge globular cluster NGC 6553

Contact Info

Product

Resources

About