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RED SUPERGIANTS AS COSMIC ABUNDANCE PROBES: THE MAGELLANIC CLOUDS

Davies, B and Kudritzki, R-P and Gazak, Z and Plez, B and Bergemann, M and Evans, C and Patrick, L (2015) RED SUPERGIANTS AS COSMIC ABUNDANCE PROBES: THE MAGELLANIC CLOUDS. ASTROPHYSICAL JOURNAL, 806 (1). ISSN 0004-637X

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Abstract

Red Supergiants (RSGs) are cool (∼ 4000K), highly luminous stars (L ∼ 105L⊙), and are among the
brightest near-infrared (NIR) sources in star-forming galaxies. This makes them powerful probes of
the properties of their host galaxies, such as kinematics and chemical abundances. We have developed
a technique whereby metallicities of RSGs may be extracted from a narrow spectral window around
1μm from only moderate resolution data. The method is therefore extremely efficient, allowing stars
at large distances to be studied, and so has tremendous potential for extragalactic abundance work.
Here, we present an abundance study of the Large and Small Magellanic Clouds (LMC and SMC
respectively) using samples of 9-10 RSGs in each. We find average abundances for the two galaxies of
[Z]LMC = −0.37±0.14 and [Z]SMC = −0.53±0.16 (with respect to a Solar metallicity of Z⊙=0.012).
These values are consistent with other studies of young stars in these galaxies, and though our result for
the SMC may appear high it is consistent with recent studies of hot stars which find 0.5-0.8dex below
Solar. Our best-fit temperatures are on the whole consistent with those from fits to the optical-infrared spectral energy distributions, which is remarkable considering the narrow spectral range being studied.
Combined with our recent study of RSGs in the Galactic cluster Per OB1, these results indicate that
this technique performs well over a range of metallicities, paving the way for forthcoming studies of
more distant galaxies beyond the Local Group.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical And Space Sciences, 0305 Organic Chemistry, 0306 Physical Chemistry (Incl. Structural)
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: IOP PUBLISHING LTD
Related URLs:
Date Deposited: 10 Apr 2017 12:04
Last Modified: 07 Sep 2017 23:50
DOI or Identification number: 10.1088/0004-637X/806/1/21
URI: http://researchonline.ljmu.ac.uk/id/eprint/4781

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