Fitting the mass–radius relation of embedded clusters in observations using N-body simulations. (a) Dashed lines are the r_h–M_ecl relations at different time nodes. Red and black dots represent the subclusters from Kuhn et al. (2014), which have ages of >1.6 Myr and <1.6 Myr, respectively. The dashed black line represents the fitted massradius relation. Here, “k” is the slope of the linear fitting with units of pc/M_⊙, and “r” is the Pearson correlation coefficient. (b) Age distribution of the subclusters in Table 1 of Kuhn et al. (2015).