Velocity dispersion vs. metallicity profile of the metal-poor bulge. A running median with bin size of 170 data points is used to construct the curve displayed as a green solid line. A 1σ error band around the mean is given by the green shaded area. The metallicity and error of the bulge knee in the [Mg/Fe] vs. [Fe/H] plane are indicated by a vertical dashed line and gray shaded area.