 ![Top: Temporal evolution of maximum velocity and velocity dispersion of $v_{\rm y}$. Bottom: Distribution function of $v_{\rm y}$ at $t = 000 L/c$. The orange line is the fitting curve with the form: $\exp[- |v_{\rm y}|/\delta v_{\rm y}]$ where $\delta v_{\rm y}$ is the velocity dispersion of $v_{\rm y}$. []{data-label="fig:0"}](./