De-reddened RC K_s luminosity function for different NSD regions. The histograms, Gaussian fits, and numbers in each panel refer to the eastward-moving stellar population (in grey) and the westward-moving stars (in red). The numbers in each panel indicate the associated region in Fig. 1. The K_{s e} and K_{s w} values indicate the mean value of the Gaussian fits and its associated uncertainty for the eastward- and westward-moving stars.