a) Median nth nearest-neighbor separations of the SMA sources vs. σ_{Nth NNS}, where each data point (black filled symbol) is labeled from N = 1,..., 10.The red symbols represent the median nth NNS for a random spatial distribution for comparison purposes (see text). b) Distribution of the first NNS (open black histogram) and the distribution of the seventh NNS (filled black histogram). The red dashed-line and the red solid-line histograms correspond to the first and seventh NNS for random spatial distributions, respectively. All the histogram bin widths correspond to the approximate SMA synthesized beam size, 3′′.