Free-fall timescale to rotational period ratio (t_ff/t_rot) versus gas mass (M_gas) of known rotating disks or toroids. Open circles correspond to the objects studied by Beltrán et al. (2011), blue dot corresponds to source G35.03+0.35 (Beltrán et al. 2014), and the red dots correspond to cores A and B of G35.20N (this work). The connecting line corresponds to the different gas mass estimates for different temperatures (see Table 4). The gray areas show the regions where circumstellar disks and toroids are found. The dashed lines correspond to spheres of mass M_gas, containing a star of mass M_∗ (e.g., 0  M_⊙ and 10  M_⊙; see Sect. 4.3.3).