Tracing the evolution of the Galactic bulge with chemodynamical modelling of alpha-elements

Friaça, Amâncio César Santos; Barbuy, B.

doi:10.1051/0004-6361/201629941

Cited by 29 publications

(32 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The lack of vertical abundance variation for different metallicity components and abundance trends similar to the high-α, or thick disk population, both point to fast chemical enrichment in the bulge (e.g., Friaça & Barbuy 2017). Furthermore, the metalpoor bulge population may have experienced a different evolution, as we observe that it is enhanced in alpha abundances compared to the high-α disk population.…”

Section: Resultsmentioning

confidence: 60%

HERBS I: Metallicity and alpha enhancement along the Galactic bulge minor axis

Duong

Asplund

Nataf

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

To better understand the origin and evolution of the Milky Way bulge, we have conducted a survey of bulge red giant branch and clump stars using the HERMES spectrograph on the Anglo-Australian Telescope. We targeted ARGOS survey stars with pre-determined bulge memberships, covering the full metallicity distribution function. The spectra have signal-tonoise ratios comparable to, and were analysed using the same methods as the GALAH survey. In this work we present the survey design, stellar parameters, distribution of metallicity and alpha-element abundances along the minor bulge axis at latitudes b = −10 • , −7.5 • and −5 • . Our analysis of ARGOS stars indicates that the centroids of ARGOS metallicity components should be located ≈0.09 dex closer together. The vertical distribution of α-element abundances is consistent with the varying contributions of the different metallicity components. Closer to the plane, alpha abundance ratios are lower as the metal-rich population dominates. At higher latitudes, the alpha abundance ratios increase as the number of metal-poor stars increases. However, we find that the trend of alpha-enrichment with respect to metallicity is independent of latitude. Comparison of our results with those of GALAH DR2 revealed that for [Fe/H] ≈ −0.8, the bulge shares the same abundance trend as the high-α disk population. However, the metal-poor bulge population ([Fe/H] −0.8) show enhanced alpha abundance ratios compared to the disk/halo. These observations point to fairly rapid chemical evolution in the bulge, and that the metal-poor bulge population does not share the same similarity with the disk as the more metal-rich populations.

show abstract

Section: Resultsmentioning

confidence: 60%

HERBS I: Metallicity and alpha enhancement along the Galactic bulge minor axis

Duong

Asplund

Nataf

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The question why the presence of PANHs is more apparent in some galaxies but not in others could be addressed with chemical evolution models taking into account differences in metallicity, star formation history and the nature of molecular clouds in the harboring galaxy, e.g. the chemodynamical model in Friaça & Barbuy (2017). In addition, further computational calculations together with laboratory measurements are needed to make more robust predictions of the role of PANHs in the profile of the PAH emission bands, mainly in the conditions prevailing in galaxies with star formation.…”

Section: Discussionmentioning

confidence: 99%

Variations in the 6.2 μm emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?

Canelo

Friaça

Sales

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Analyses of the polycyclic aromatic hydrocarbon (PAH) feature profiles, especially the 6.2 µm feature, could indicate the presence of nitrogen incorporated in their aromatic rings. In this work, 155 predominantly starburst-dominated galaxies (including HII regions and Seyferts, for example), extracted from the Spitzer/IRS ATLAS project (Hernán-Caballero & Hatziminaoglou 2011), have their 6.2 µm profiles fitted allowing their separation into the Peeters' A, B and C classes (Peeters et al. 2002). 67% of these galaxies were classified as class A, 31% were as class B and 2% as class C. Currently class A sources, corresponding to a central wavelength near 6.22 µm, seem only to be explained by polycyclic aromatic nitrogen heterocycles (PANH, Hudgins et al. 2005), whereas class B may represent a mix between PAHs and PANHs emissions or different PANH structures or ionization states. Therefore, these spectra suggest a significant presence of PANHs in the interstellar medium (ISM) of these galaxies that could be related to their starburst-dominated emission. These results also suggest that PANHs constitute another reservoir of nitrogen in the Universe, in addition to the nitrogen in the gas phase and ices of the ISM.

show abstract

“…These were the bulge dwarfs by Bensby et al (2013), the red giant stars from Alves-Brito et al (2010) that were carried out in the optical for the same stars as in Meléndez et al (2008), Cunha & Smith (2006), Ryde et al (2010), Rich et al (2012), Johnson et al (2014), Rich & Origlia (2005) and Fulbright et al (2007). Zoccali et al (2006), N, O abundances are from Friaça & Barbuy (2017 We now compare the present oxygen abundances for the GIRAFFE sample together with those from the UVES sample, given in FB17, compared with: a) the reanalysis of stellar parameters carried out by Jönsson et al (2017) for 23 stars of the same UVES data, for which they derived oxygen abundances, except for one of them (B3-f1) that FB17 did not include in their study; b) Ryde et al (2010) where five stars of our UVES sample were included, plus another six stars; c) recent results by Schultheis et al (2017), where comparisons with a fraction of the present stars were given; d) recent results for microlensed dwarf stars by Bensby et al (2017). ] values for model changes of ∆T eff = 150, 200 K, ∆log g = +0.2, 0.4, ∆v t = +0.1, 0.2, 0.3 km s −1 , for UVES and GIRAFFE data respectively, and corresponding total error, applied to the stellar parameters T eff , log g, [Fe/H], v t of stars BW-b6 (4200 K, 1.7, −0.25, 1.3 km.s −1 ), and B6-b3 (4700 K, 2.0, 0.10, 1.6 km.s −1 ).…”

Section: Oxygen Abundancesmentioning

confidence: 99%

“…Oxygen abundances in bulge field stars have been derived in several studies, among which the most recent are Alves-Brito et al (2010), Bensby et al (2013), Friaça & Barbuy (2017), Send offprint requests to: B. Barbuy Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A); Table B.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgibin/qcat?J/A+A/ Johnson et al (2014), Jönsson et al (2017), Meléndez et al (2008), Rich et al (2012), Ryde et al (2010), Schultheis et al (2017), and Siqueira-Mello et al (2016).…”

Section: Introductionmentioning

confidence: 99%

Oxygen and zinc abundances in 417 Galactic bulge red giants

Silveira

Barbuy

Friaça

et al. 2018

A&A

Self Cite

View full text Add to dashboard Cite

Context. Oxygen and zinc in the Galactic bulge are key elements for the understanding of the bulge chemical evolution. Oxygen-toiron abundance ratios provide a most robust indicator of the star formation rate and chemical evolution of the bulge. Zinc is enhanced in metal-poor stars, behaving as an α-element, and its production may require nucleosynthesis in hypernovae. Most of the neutral gas at high redshift is in damped Lyman-alpha systems (DLAs), where Zn is also observed to behave as an α-element. Aims. The aim of this work is the derivation of the α-element oxygen, together with nitrogen, and the iron-peak element zinc abundances in 417 bulge giants, from moderate resolution (R∼22,000) FLAMES-GIRAFFE spectra. For stars in common with a set of UVES spectra with higher resolution (R∼45,000), the data are intercompared. The results are compared with literature data and chemodynamical models. Methods. We studied the spectra obtained for a large sample of red giant stars, chosen to be one magnitude above the horizontal branch, using FLAMES-GIRAFFE on the Very Large Telescope. We computed the O abundances using the forbidden [OI] 6300.3 Å and Zn abundances using the Zn I 6362.34 Å lines. Stellar parameters for these stars were established in a previous work from our group. Results. We present oxygen abundances for 358 stars, nitrogen abundances for 403 stars and zinc abundances were derived for 333 stars. Having oxygen abundances for this large sample adds information in particular at the moderate metallicities of -1.6<[Fe/H]<-0.8. Zn behaves as an α-element, very similarly to O, Si, and Ca. It shows the same trend as a function of metallicity as the α-elements, i.e., a turnover around [Fe/H]∼-0.6, and then decreasing with increasing metallicity. The results are compared with chemodynamical evolution models of O and Zn enrichment for a classical bulge. DLAs also show an enhanced zinc-to-iron ratio, suggesting they may be enriched by hypernovae.

show abstract

Tracing the evolution of the Galactic bulge with chemodynamical modelling of alpha-elements

Cited by 29 publications

References 70 publications

HERBS I: Metallicity and alpha enhancement along the Galactic bulge minor axis

HERBS I: Metallicity and alpha enhancement along the Galactic bulge minor axis

Variations in the 6.2 μm emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?

Oxygen and zinc abundances in 417 Galactic bulge red giants

Contact Info

Product

Resources

About