High-resolution abundance analysis of red giants in the metal-poor bulge globular cluster HP 1

Barbuy, B.; Cantelli, E.; Vemado, A.; Ernandes, H.; Ortolani, S.; Saviane, I.; Bica, E.; Minniti, D.; Dias, B.; Momany, Y.; Hill, V.; Zoccali, M.; Siqueira-Mello, C.

doi:10.1051/0004-6361/201628106

Cited by 40 publications

(86 citation statements)

References 88 publications

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“…The radial velocity of this probable HP1 star is 42.25±2.75 km s −1 . This value is in agreement with that computed by Barbuy et al (2016). The axisymmetric Galactic model includes a Sérsic bulge, an exponential disc generated by the superposition of three Miyamoto-Nagai potentials (Miyamoto & Nagai 1975), following the methodology made by Smith et al (2015), and a dark matter halo is modelled with the Navarro-Frenk-White (NFW) density profile (Navarro et al 1997), having a circular velocity V 0 = 241 km s −1 at R 0 = 8.2 kpc (Bland-Hawthorn & Gerhard 2016).…”

Section: Orbital Analysis Of Hpsupporting

confidence: 93%

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A deep view of a fossil relic in the Galactic bulge: the Globular Cluster HP 1

Kerber

Libralato

Souza

et al. 2019

Monthly Notices of the Royal Astronomical Society

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HP 1 is an α-enhanced and moderately metal-poor bulge globular cluster with a blue horizontal branch. These combined characteristics make it a probable relic of the early star formation in the innermost Galactic regions. Here we present a detailed analysis of a deep near-infrared (NIR) photometry of HP 1 obtained with the NIR GSAOI+GeMS camera at the Gemini-South telescope. J and K S images were collected with an exquisite spatial resolution (FWHM ∼ 0.1 arcsec), reaching stars at two magnitudes below the MSTO. We combine our GSAOI data with archival F606Wfilter HST ACS/WFC images to compute relative proper motions and select bona fide cluster members. Results from statistical isochrone fits in the NIR and optical-NIR colour-magnitude diagrams indicate an age of 12.8 +0.9 −0.8 Gyr, confirming that HP 1 is one of the oldest clusters in the Milky Way. The same fits also provide apparent distance moduli in the K S and V filters in very good agreement with the ones from 11 RR Lyrae stars. By subtracting the extinction in each filter, we recover a heliocentric distance of 6.59 +0.17 −0.15 kpc. Furthermore, we refine the orbit of HP 1 using this accurate distance and update and accurate radial velocities (from high resolution spectroscopy) and absolute proper motions (from Gaia DR2), reaching mean perigalactic and apogalactic distances of ∼0.12 and ∼3 kpc respectively.

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Section: Orbital Analysis Of Hpsupporting

confidence: 93%

“…CMDs. Interpolations in metallicity were performed in order to compute isochrones with −1.26 ≤ [Fe/H] ≤ −0.86 in steps of 0.02 dex, therefore fully covering the accurate value of [Fe/H]= −1.06 ± 0.10 from high-resolution spectroscopic analysis of Barbuy et al (2016).…”

Section: Stellar Evolutionary Modelsmentioning

confidence: 99%

A deep view of a fossil relic in the Galactic bulge: the Globular Cluster HP 1

Kerber

Libralato

Souza

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…Moreover, our finding show good compatibility with the result of Barbuy et al (2016), they concluded that abundances of HP1 agree with enrichment by SNII at early epoch, our result show a good agreement with enrichment by SNIa, which happen later. These results are indication that NGC6528 is younger that HP1, which would be expected by its metallicity.…”

Section: Iron-peak Elementssupporting

confidence: 88%

Chemical analysis of NGC 6528: one of the most metal-rich bulge globular clusters

Muñoz

Geisler

Villanova

et al. 2018

A&A

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Context. The Bulge Globular Clusters (GCs) are key tracers of this central ancient component of our Galaxy. It is essential to understand their formation and evolution to study that of the bulge, as well as their relationship with the other Galactic GC systems (halo and disk GCs). High resolution spectroscopy is a powerful tool for such studies, allowing us to obtain a detailed chemical characterization and kinematics of the clusters and to compare their chemical patterns with those of their halo and disk counterparts. Aims. Our main goals are to obtain detailed abundances for a sample of seven red giant members of NGC 6528 in order to characterize its chemical composition and study the relationship of this GC with the bulge, and with other bulge, halo and disk GCs. Moreover, we analyze this cluster's behavior associated with the Multiple Populations (MPs) phenomenon. Methods. We obtained the stellar parameters and chemical abundances of light elements (Na, Al), iron-peak elements (V, Cr, Mn, Fe, Co, Ni, Cu), α-elements (O, Mg, Si, Ca, Ti) and heavy elements (Zr, Ba, Eu) in seven red giant members of NGC 6528 using high resolution spectroscopy from FLAMES-UVES. Results. We obtained in six stars of our sample a mean iron content of [Fe/H]=-0.14±0.03 dex, in good agreement with other studies. We found no significant internal iron spread. We detected one candidate variable star, which was excluded from the mean in iron content, we derived a metallicity in this star of [Fe/H]=-0.55±0.04 dex. Moreover, we found no extended O-Na anticorrelation but instead only an intrinsic Na spread. In addition, NGC 6528 does not exhibit a Mg-Al anticorrelation, and no significant spread in either Mg or Al. The α and iron-peak elements show good agreement with the bulge field star trend. The heavy elements are slightly dominated by the r-process. The chemical analysis suggests an origin and evolution similar to that of typical old Bulge field stars. Finally, we find remarkable agreement in the chemical patterns of NGC 6528 and another bulge GC, NGC 6553, suggesting a similar origin and evolution.

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“…In the present work we analyse individual stars in the reference globular cluster 47 Tucanae ([Fe/H] 1 = −0.67, Alves-Brito et al 2005), and the bulge globular clusters NGC 6553 ([Fe/H] = −0.20, Alves-Brito et al 2006), NGC 6528 ([Fe/H] = −0.11, Zoccali et al 2004), NGC 6522 ([Fe/H] = −0.95, , HP 1 ([Fe/H] = −1.00, Barbuy et al 2006Barbuy et al , 2016, and NGC 6558 ([Fe/H] = −1.00, Barbuy et al 2017). In previous work we have derived the abundances of the α-elements (O, Mg, Ca, Si, Ti), odd-Z (Na, Al), s-process (Ba, La, Zr), and r-process 1 We adopted here the usual spectroscopic notation that [A/B] = log(NA/NB) − log(NA/NB) and (A) = log(NA/NB) + 12 for each elements A and B.…”

Section: Introductionmentioning

confidence: 99%

Iron-peak elements Sc, V, Mn, Cu, and Zn in Galactic bulge globular clusters

Ernandes

Barbuy

Alves-Brito

et al. 2018

A&A

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Aims. Globular clusters are tracers of the history of star formation and chemical enrichment in the early Galaxy. Their abundance pattern can help understanding their chemical enrichment processes. In particular, the iron-peak elements have been relatively little studied so far in the Galactic bulge. Methods. The main aim of this work is to verify the strength of abundances of iron-peak elements for chemical tagging in view of identifying different stellar populations. Besides, the nucleosynthesis processes that build these elements are complex, therefore observational data can help constraining theoretical models, as well as give hints on the kinds of supernovae that enriched the gas before these stars formed.Results. The abundances of iron-peak elements are derived for the sample clusters, and compared with bulge field, and thick disk stars. We derive abundances of the iron-peak elements Sc, V, Mn, Cu, and Zn in individual stars of five bulge globular clusters (NGC 6528, NGC 6553, NGC 6522, NGC 6558, HP 1), and of the reference thick disk/inner halo cluster 47 Tucanae (NGC 104). High resolution spectra were obtained with the UVES spectrograph at the Very Large Telescope over the years.Conclusions. The sample globular clusters studied span metallicities in the range -1.2 < ∼ [Fe/H] < ∼ 0.0. V and Sc appear to vary in lockstep with Fe, indicating that they are produced in the same supernovae as Fe. We find that Mn is deficient in metal-poor stars, confirming that it is underproduced in massive stars; Mn-over-Fe steadily increases at the higher metallicities due to a metallicity-dependent enrichment by supernovae of type Ia. Cu behaves as a secondary element, indicating its production in a weak-s process in massive stars. Zn has an alpha-like behaviour at low metallicities, which can be explained in terms of nucleosynthesis in hypernovae. At the metal-rich end, Zn decreases with increasing metallicity, similarly to the alpha-elements.

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High-resolution abundance analysis of red giants in the metal-poor bulge globular cluster HP 1

Cited by 40 publications

References 88 publications

A deep view of a fossil relic in the Galactic bulge: the Globular Cluster HP 1

A deep view of a fossil relic in the Galactic bulge: the Globular Cluster HP 1

Chemical analysis of NGC 6528: one of the most metal-rich bulge globular clusters

Iron-peak elements Sc, V, Mn, Cu, and Zn in Galactic bulge globular clusters

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