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

A. Recio-Blanco, A. Rojas-Arriagada, P. De Laverny, S. Mikolaitis, V. Hill, M. Zoccali, J. G. Fernández-Trincado, A. C. Robin, C. Babusiaux, G. Gilmore, S. Randich, E. Alfaro, C. Allende Prieto, A. Bragaglia, G. Carraro, P. Jofré, C. Lardo, L. Monaco, L. Morbidelli, S. Zaggia

Resultado de la investigación: Article

17 Citas (Scopus)

Resumen

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.

Idioma originalEnglish
Número de artículoL14
PublicaciónAstronomy and Astrophysics
Volumen602
DOI
EstadoPublished - 1 jun 2017

Huella dactilar

galactic bulge
European Southern Observatory
stars
deviation
composite materials
dwarf galaxies
globular clusters
aluminum
accretion
anomalies
trends
anomaly
high resolution

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Recio-Blanco, A., Rojas-Arriagada, A., De Laverny, P., Mikolaitis, S., Hill, V., Zoccali, M., ... Zaggia, S. (2017). The Gaia-ESO Survey: Low-α element stars in the Galactic bulge. Astronomy and Astrophysics, 602, [L14]. https://doi.org/10.1051/0004-6361/201630220
Recio-Blanco, A. ; Rojas-Arriagada, A. ; De Laverny, P. ; Mikolaitis, S. ; Hill, V. ; Zoccali, M. ; Fernández-Trincado, J. G. ; Robin, A. C. ; Babusiaux, C. ; Gilmore, G. ; Randich, S. ; Alfaro, E. ; Allende Prieto, C. ; Bragaglia, A. ; Carraro, G. ; Jofré, P. ; Lardo, C. ; Monaco, L. ; Morbidelli, L. ; Zaggia, S. / The Gaia-ESO Survey : Low-α element stars in the Galactic bulge. En: Astronomy and Astrophysics. 2017 ; Vol. 602.
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abstract = "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.",
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Recio-Blanco, A, Rojas-Arriagada, A, De Laverny, P, Mikolaitis, S, Hill, V, Zoccali, M, Fernández-Trincado, JG, Robin, AC, Babusiaux, C, Gilmore, G, Randich, S, Alfaro, E, Allende Prieto, C, Bragaglia, A, Carraro, G, Jofré, P, Lardo, C, Monaco, L, Morbidelli, L & Zaggia, S 2017, 'The Gaia-ESO Survey: Low-α element stars in the Galactic bulge', Astronomy and Astrophysics, vol. 602, L14. https://doi.org/10.1051/0004-6361/201630220

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.; Fernández-Trincado, J. G.; Robin, A. C.; Babusiaux, C.; Gilmore, G.; Randich, S.; Alfaro, E.; Allende Prieto, C.; Bragaglia, A.; Carraro, G.; Jofré, P.; Lardo, C.; Monaco, L.; Morbidelli, L.; Zaggia, S.

En: Astronomy and Astrophysics, Vol. 602, L14, 01.06.2017.

Resultado de la investigación: Article

TY - JOUR

T1 - The Gaia-ESO Survey

T2 - Low-α element stars in the Galactic bulge

AU - Recio-Blanco, A.

AU - Rojas-Arriagada, A.

AU - De Laverny, P.

AU - Mikolaitis, S.

AU - Hill, V.

AU - Zoccali, M.

AU - Fernández-Trincado, J. G.

AU - Robin, A. C.

AU - Babusiaux, C.

AU - Gilmore, G.

AU - Randich, S.

AU - Alfaro, E.

AU - Allende Prieto, C.

AU - Bragaglia, A.

AU - Carraro, G.

AU - Jofré, P.

AU - Lardo, C.

AU - Monaco, L.

AU - Morbidelli, L.

AU - Zaggia, S.

PY - 2017/6/1

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N2 - 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.

AB - 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.

KW - Galaxy: abundances

KW - Galaxy: bulge

KW - Galaxy: stellar content

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Recio-Blanco A, Rojas-Arriagada A, De Laverny P, Mikolaitis S, Hill V, Zoccali M y otros. The Gaia-ESO Survey: Low-α element stars in the Galactic bulge. Astronomy and Astrophysics. 2017 jun 1;602. L14. https://doi.org/10.1051/0004-6361/201630220