Infall time distributions in the eight zones of the linear partition method. The zone numbers are indicated in the upper right corners. The blue shadings represent the t_fall distributions constructed via Gaussian kernel density estimation with a kernel size of 0.3 Gyr. The black vertical lines indicate the median t_fall in each zone. The blue and red curves are the two components obtained through the GMM, with the blue and red dashed lines indicating their peak locations.