Velocity dispersion histogram extracted from the optimally decomposed Gaussian components (open histogram). The gray-shaded histogram is that for the bulk components. Two Gaussians describe the bimodality of the histogram and they overlap at 4.0 km s⁻¹ (black dotted line). The blue dashed line presents cool-bulk components (v _disp < 4.0 km s⁻¹) and the red dashed-dotted line shows the warm-bulk distribution (v _disp > 4.0 km s⁻¹).