Red Supergiants as Cosmic Abundance Probes: The Magellanic Clouds
  Red Supergiants (RSGs) are cool (~4000K), highly luminous stars (L - 10^5
Lsun), 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 1{\mu}m 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 Zsun=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.
