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Red Supergiants as Chemical Abundance Probes: The Local Group dwarf NGC6822

Published online by Cambridge University Press:  30 October 2019

Lee R. Patrick Open the ORCID record for Lee R. Patrick [Opens in a new window] ,
Chris J. Evans ,
Ben Davies ,
Rolf-Peter Kudritzki ,
Maria Bergemann  and
Annette N. M. Ferguson
Lee R. Patrick
Affiliation:
Instituto de Astrofísica de Canarias, E-38205, La Laguna, Tenerife, Spain email: lpatrick@iac.es Universidad de La Laguna, Dpto. Astrofísica, E-38206, La Laguna, Tenerife, Spain
Chris J. Evans
Affiliation:
UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
Ben Davies
Affiliation:
Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park ic2, 146 Brownlow Hill, Liverpool L3 5RF, UK
Rolf-Peter Kudritzki
Affiliation:
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
Maria Bergemann
Affiliation:
Max-Planck Institute for Astronomy, D-69117, Heidelberg, Germany
Annette N. M. Ferguson
Affiliation:
Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
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Abstract

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Red Supergiant Stars (RSGs) are important probes of stellar and chemical evolution in star-forming environments. They represent the brightest near-IR stellar components of external galaxies and probe the most recent stellar population to provide robust, independent abundance estimates. The Local Group dwarf irregular galaxy, NGC6822, is a reasonably isolated galaxy with an interesting structure and turbulent history. Using RSGs as chemical abundance probes, we estimate metallicities in the central region of NGC6822, finding a suggestion of a metallicity gradient (in broad agreement with nebular tracers), however, this requires further study for confirmation. With intermediate resolution Multi-object spectroscopy (from e.g. KMOS, EMIR, MOSFIRE) combined with state-of-the-art stellar model atmospheres, we demonstrate how RSGs can be used to estimate stellar abundances in external galaxies. In this context, we compare stellar and nebular abundance tracers in NGC 6822 and by combining stellar and nebular tracers we estimate an abundance gradient of −0.18 ± 0.05 dex/kpc.

Keywords

stars: abundances(stars:) supergiantsgalaxies: abundancesgalaxies: dwarfinfrared: stars
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 14 , Symposium S344: Dwarf Galaxies: From the Deep Universe to the Present , August 2018 , pp. 213 - 216
Copyright
© International Astronomical Union 2019 

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