SIMBAD references

2017A&A...602L..14R - Astronomy and Astrophysics, volume 602, L14-14 (2017/6-1)

The Gaia-ESO Survey: Low-α element stars in the Galactic bulge.

RECIO-BLANCO A., ROJAS-ARRIAGADA A., DE LAVERNY P., MIKOLAITIS S., HILL V., ZOCCALI M., FERNANDEZ-TRINCADO J.G., ROBIN A.C., BABUSIAUX C., GILMORE G., RANDICH S., ALFARO E., ALLENDE PRIETO C., BRAGAGLIA A., CARRARO G., JOFRE P., LARDO C., MONACO L., MORBIDELLI L. and ZAGGIA S.

Abstract (from CDS):

We take advantage of the Gaia-ESO Survey iDR4 bulge data to search for abundance anomalies that could shed light on the composite nature of the Milky Way bulge. The α-element (Mg, Si, and whenever available, Ca) abundances, and their trends with Fe abundances have been analysed for a total of 776 bulge stars. In addition, the aluminum abundances and their ratio to Fe and Mg have also been examined. Our analysis reveals the existence of low-α element abundance stars with respect to the standard bulge sequence in the [α/Fe] versus [Fe/H] plane. Eighteen objects present deviations in [α/Fe] ranging from 2.1 to 5.3σ with respect to the median standard value. Those stars do not show Mg-Al anti-correlation patterns. Incidentally, this sign of the existence of multiple stellar populations is reported firmly for the first time for the bulge globular cluster NGC 6522. The identified low-α abundance stars have chemical patterns that are compatible with those of the thin disc. Their link with massive dwarf galaxies accretion seems unlikely, as larger deviations in α abundance and Al would be expected. The vision of a bulge composite nature and a complex formation process is reinforced by our results. The approach used, which is a multi-method and model-driven analysis of high resolution data, seems crucial to reveal this complexity.

Abstract Copyright: © ESO, 2017

Journal keyword(s): Galaxy: bulge - Galaxy: abundances - Galaxy: stellar content - Galaxy: stellar content

Simbad objects: 27

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2020.02.29-06:08:31

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