Zinc abundances in Galactic bulge field red giants: Implications for damped Lyman- α systems ∗ ∗ ∗

B. Barbuy, A. C.S. Friaça, C. R. Da Silveira, V. Hill, M. Zoccali, D. Minniti, A. Renzini, S. Ortolani, A. Gómez

Resultado de la investigación: Article

Resumen

Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman- systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman- systems, in order to better understand the chemical evolution in these environments. Methods. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 We considered the strong depression in the continuum of the Zn i 6362.34 line, which is caused by the wings of the Ca i 6361.79 line suffering from autoionization. CN lines blending the Zn i 6362.34 A line are also included in the calculations. Results. We find [Zn/Fe] = +0.24 ?0.02 in the range a'1.3 < [Fe/H] < a'0.5 and [Zn/Fe] = +0.06 ?0.02 in the range a'0.5 < [Fe/H] < a'0.1, whereas for [Fe/H] ≥ a'0.1, it shows a spread of a'0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution.

Idioma originalEnglish
Número de artículoA44
PublicaciónAstronomy and Astrophysics
Volumen580
DOI
EstadoPublished - 1 ago 2015

Huella dactilar

galactic bulge
zinc
chemical evolution
stars
metallicity
high resolution
spheroids
autoionization
nuclear fusion
wings
halos
depletion
dust
histories
telescopes
continuums
trends
iron
metal
history

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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Barbuy, B. ; Friaça, A. C.S. ; Da Silveira, C. R. ; Hill, V. ; Zoccali, M. ; Minniti, D. ; Renzini, A. ; Ortolani, S. ; Gómez, A. / Zinc abundances in Galactic bulge field red giants : Implications for damped Lyman- α systems ∗ ∗ ∗. En: Astronomy and Astrophysics. 2015 ; Vol. 580.
@article{595cc72e0eff48ad9110278c17b42447,
title = "Zinc abundances in Galactic bulge field red giants: Implications for damped Lyman- α systems ∗ ∗ ∗",
abstract = "Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman- systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman- systems, in order to better understand the chemical evolution in these environments. Methods. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 We considered the strong depression in the continuum of the Zn i 6362.34 line, which is caused by the wings of the Ca i 6361.79 line suffering from autoionization. CN lines blending the Zn i 6362.34 A line are also included in the calculations. Results. We find [Zn/Fe] = +0.24 ?0.02 in the range a'1.3 < [Fe/H] < a'0.5 and [Zn/Fe] = +0.06 ?0.02 in the range a'0.5 < [Fe/H] < a'0.1, whereas for [Fe/H] ≥ a'0.1, it shows a spread of a'0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution.",
keywords = "Galaxies: evolution, Galaxy: bulge, Stars: abundances",
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Barbuy, B, Friaça, ACS, Da Silveira, CR, Hill, V, Zoccali, M, Minniti, D, Renzini, A, Ortolani, S & Gómez, A 2015, 'Zinc abundances in Galactic bulge field red giants: Implications for damped Lyman- α systems ∗ ∗ ∗', Astronomy and Astrophysics, vol. 580, A44. https://doi.org/10.1051/0004-6361/201525694

Zinc abundances in Galactic bulge field red giants : Implications for damped Lyman- α systems ∗ ∗ ∗. / Barbuy, B.; Friaça, A. C.S.; Da Silveira, C. R.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.

En: Astronomy and Astrophysics, Vol. 580, A44, 01.08.2015.

Resultado de la investigación: Article

TY - JOUR

T1 - Zinc abundances in Galactic bulge field red giants

T2 - Implications for damped Lyman- α systems ∗ ∗ ∗

AU - Barbuy, B.

AU - Friaça, A. C.S.

AU - Da Silveira, C. R.

AU - Hill, V.

AU - Zoccali, M.

AU - Minniti, D.

AU - Renzini, A.

AU - Ortolani, S.

AU - Gómez, A.

PY - 2015/8/1

Y1 - 2015/8/1

N2 - Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman- systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman- systems, in order to better understand the chemical evolution in these environments. Methods. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 We considered the strong depression in the continuum of the Zn i 6362.34 line, which is caused by the wings of the Ca i 6361.79 line suffering from autoionization. CN lines blending the Zn i 6362.34 A line are also included in the calculations. Results. We find [Zn/Fe] = +0.24 ?0.02 in the range a'1.3 < [Fe/H] < a'0.5 and [Zn/Fe] = +0.06 ?0.02 in the range a'0.5 < [Fe/H] < a'0.1, whereas for [Fe/H] ≥ a'0.1, it shows a spread of a'0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution.

AB - Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman- systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman- systems, in order to better understand the chemical evolution in these environments. Methods. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 We considered the strong depression in the continuum of the Zn i 6362.34 line, which is caused by the wings of the Ca i 6361.79 line suffering from autoionization. CN lines blending the Zn i 6362.34 A line are also included in the calculations. Results. We find [Zn/Fe] = +0.24 ?0.02 in the range a'1.3 < [Fe/H] < a'0.5 and [Zn/Fe] = +0.06 ?0.02 in the range a'0.5 < [Fe/H] < a'0.1, whereas for [Fe/H] ≥ a'0.1, it shows a spread of a'0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution.

KW - Galaxies: evolution

KW - Galaxy: bulge

KW - Stars: abundances

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U2 - 10.1051/0004-6361/201525694

DO - 10.1051/0004-6361/201525694

M3 - Article

AN - SCOPUS:84938083534

VL - 580

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

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