Chrono-chemodynamical analysis of the globular cluster NGC 6355 : Looking for the fundamental bricks of the Bulge
(2023) In Astronomy and Astrophysics 671.- Abstract
The information on Galactic assembly time is imprinted on the chemodynamics of globular clusters. This makes them important probes that help us to understand the formation and evolution of the Milky Way. Discerning between in-situ and ex-situ origin of these objects is difficult when we study the Galactic bulge, which is the most complex and mixed component of the Milky Way. To investigate the early evolution of the Galactic bulge, we analysed the globular cluster NGC 6355. We derived chemical abundances and kinematic and dynamic properties by gathering information from high-resolution spectroscopy with FLAMES-UVES, photometry with the Hubble Space Telescope, and Galactic dynamic calculations applied to the globular cluster NGC 6355. We... (More)
The information on Galactic assembly time is imprinted on the chemodynamics of globular clusters. This makes them important probes that help us to understand the formation and evolution of the Milky Way. Discerning between in-situ and ex-situ origin of these objects is difficult when we study the Galactic bulge, which is the most complex and mixed component of the Milky Way. To investigate the early evolution of the Galactic bulge, we analysed the globular cluster NGC 6355. We derived chemical abundances and kinematic and dynamic properties by gathering information from high-resolution spectroscopy with FLAMES-UVES, photometry with the Hubble Space Telescope, and Galactic dynamic calculations applied to the globular cluster NGC 6355. We derive an age of 13:2 ± 1:1 Gyr and a metallicity of [Fe/H] =-1:39 ± 0:08 for NGC 6355, with α-enhancement of [α/Fe] = +0:37 ± 0:11. The abundance pattern of the globular cluster is compatible with bulge field RR Lyrae stars and in-situ well-studied globular clusters. The orbital parameters suggest that the cluster is currently confined within the bulge volume when we consider a heliocentric distance of 8:54 ± 0:19 kpc and an extinction coefficient of RV = 2:84 ± 0:02. NGC 6355 is highly likely to come from the main bulge progenitor. Nevertheless, it still has a low probability of being formed from an accreted event because its age is uncertain and because of the combined [Mg/Mn] [Al/Fe] abundance. Its relatively low metallicity with respect to old and moderately metal-poor inner Galaxy clusters may suggest a low-metallicity floor for globular clusters that formed in-situ in the early Galactic bulge.
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- author
- Souza, S. O. ; Ernandes, H. LU ; Valentini, M. ; Barbuy, B. ; Chiappini, C. ; Pérez-Villegas, A. ; Ortolani, S. ; Friaça, A. C.S. ; Queiroz, A. B.A. and Bica, E.
- organization
- publishing date
- 2023-03-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Galaxy: bulge, Galaxy: kinematics and dynamics, Globular clusters: individual: NGC 6355, Hertzsprung-Russell and C-M diagrams, Stars: Abundances, Stars: Atmospheres
- in
- Astronomy and Astrophysics
- volume
- 671
- article number
- A45
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85149646035
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202245286
- language
- English
- LU publication?
- yes
- id
- 76018b0c-6841-4c68-919b-a22c99abbfe1
- date added to LUP
- 2023-06-09 14:27:19
- date last changed
- 2024-04-19 22:43:25
@article{76018b0c-6841-4c68-919b-a22c99abbfe1,
abstract = {{<p>The information on Galactic assembly time is imprinted on the chemodynamics of globular clusters. This makes them important probes that help us to understand the formation and evolution of the Milky Way. Discerning between in-situ and ex-situ origin of these objects is difficult when we study the Galactic bulge, which is the most complex and mixed component of the Milky Way. To investigate the early evolution of the Galactic bulge, we analysed the globular cluster NGC 6355. We derived chemical abundances and kinematic and dynamic properties by gathering information from high-resolution spectroscopy with FLAMES-UVES, photometry with the Hubble Space Telescope, and Galactic dynamic calculations applied to the globular cluster NGC 6355. We derive an age of 13:2 ± 1:1 Gyr and a metallicity of [Fe/H] =-1:39 ± 0:08 for NGC 6355, with α-enhancement of [α/Fe] = +0:37 ± 0:11. The abundance pattern of the globular cluster is compatible with bulge field RR Lyrae stars and in-situ well-studied globular clusters. The orbital parameters suggest that the cluster is currently confined within the bulge volume when we consider a heliocentric distance of 8:54 ± 0:19 kpc and an extinction coefficient of RV = 2:84 ± 0:02. NGC 6355 is highly likely to come from the main bulge progenitor. Nevertheless, it still has a low probability of being formed from an accreted event because its age is uncertain and because of the combined [Mg/Mn] [Al/Fe] abundance. Its relatively low metallicity with respect to old and moderately metal-poor inner Galaxy clusters may suggest a low-metallicity floor for globular clusters that formed in-situ in the early Galactic bulge.</p>}},
author = {{Souza, S. O. and Ernandes, H. and Valentini, M. and Barbuy, B. and Chiappini, C. and Pérez-Villegas, A. and Ortolani, S. and Friaça, A. C.S. and Queiroz, A. B.A. and Bica, E.}},
issn = {{0004-6361}},
keywords = {{Galaxy: bulge; Galaxy: kinematics and dynamics; Globular clusters: individual: NGC 6355; Hertzsprung-Russell and C-M diagrams; Stars: Abundances; Stars: Atmospheres}},
language = {{eng}},
month = {{03}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{Chrono-chemodynamical analysis of the globular cluster NGC 6355 : Looking for the fundamental bricks of the Bulge}},
url = {{http://dx.doi.org/10.1051/0004-6361/202245286}},
doi = {{10.1051/0004-6361/202245286}},
volume = {{671}},
year = {{2023}},
}