Normalized histograms for each of the galactic coordinates in red, as shown in Fig. 6 and the corresponding histograms of the permuted sample in blue. The distances between the means of the red and the blue distributions in the the quadrants α, β, γ, and δ are 2.3σ, 2.5σ, 3.2σ, and 0.61σ, respectively. The α quadrant shows the most significant gradient. If we assume a 3σ cutoff, this gradient is the only one unlikely to be explained by chance. The varying significance is due to the corresponding stellar counts, see text for details.