Building on our previous spectroscopic and photometric analysis of the isolated Local Group dwarf irregular ( dIrr ) galaxy WLM , we present a comparison of the metallicities of its RGB stars with respect to the well studied Local Group dwarf spheroidal galaxies ( dSphs ) and Magellanic Clouds .
We calculate a mean metallicity of [ Fe/H ] = -1.28 \pm 0.02 , and intrinsic spread in metallicity of \sigma = 0.38 \pm 0.04 dex , similar to the mean and spread observed in the massive dSph Fornax and the Small Magellanic Cloud .
Thus , despite its isolated environment the global metallicity still follows expectations for WLM ’ s mass and its global chemical evolution is similar to other nearby luminous dwarf galaxies ( gas-rich or gas-poor ) .
The data also show a radial gradient in [ Fe/H ] of { d [ Fe / H ] / dr _ { c } } = -0.04 \pm 0.04 dex { r _ { c } ^ { -1 } } , which is flatter than that seen in the unbiased and spatially extended surveys of dSphs .
Comparison of the spatial distribution of [ Fe/H ] in WLM , the Magellanic Clouds , and a sample of Local Group dSphs , shows an apparent dichotomy in the sense that the dIrrs have statistically flatter radial [ Fe/H ] gradients than the low angular momentum dSphs .
The correlation between angular momentum and radial metallicity gradient is further supported when considering the Local Group dEs .
This chemodynamic relationship offers a new and useful constraint for environment driven dwarf galaxy evolution models in the Local Group .