Abstract:
We have derived high-spatial-resolution metallicity maps covering ∼105 deg2 across the Large Magellanic Cloud (LMC) using
near-infrared passbands from the VISTA Survey of the Magellanic Clouds. We attempt to understand the metallicity distribution
and gradients of the LMC up to a radius of ∼6 kpc. We identify red giant branch (RGB) stars in spatially distinct Y, (Y − Ks)
colour–magnitude diagrams. In any of our selected subregions, the RGB slope is used as an indicator of the average metallicity,
based on calibration to metallicity using spectroscopic data. The mean LMC metallicity is [Fe/H] = −0.42 dex (σ[Fe/H] =
0.04 dex). We find the bar to be mildly metal-rich compared with the outer disc, showing evidence of a shallow gradient in
metallicity (−0.008 ± 0.001 dex kpc−1) from the galaxy’s centre to a radius of 6 kpc. Our results suggest that the LMC’s stellar
bar is chemically similar to the bars found in large spiral galaxies. The LMC’s radial metallicity gradient is asymmetric. It is
metal-poor and flatter towards the southwest, in the direction of the Bridge. This hints at mixing and/or distortion of the spatial
metallicity distribution, presumably caused by tidal interactions between the Magellanic Clouds.
