Panel (a): relationship for the SMC clouds. The red dots show the CO clouds of this work, whose Σ was calculated from their luminous mass assuming the Galactic conversion factor. The green dots correspond to the dust clouds identified by Takekoshi et al. (2017) at 12 pc resolution. Their Σ were calculated from the dust-based total gas mass by these authors and the velocity dispersion by mean Eq. (15). The black curves indicate gravitational virial conditions for clouds confined by external pressures from P_ext/k_B = 10² to 10⁶ Kcm⁻³. The straight solid line corresponds to virialized clouds without pressure, and the dashed line is the marginal gravitationally bound condition (identical kinetic and gravitational energy). Panel (b): birial parameter (α_vir) vs. dust-based total gas mass for the same SMC dust clouds shown in panel (a). We have added for comparison the virial parameters of the Milky Way (squares) and SMC GMCs (star symbols) from Bot et al. (2007, Bot et al. 2010), and the LMC GMCs (empty circles) from Herrera et al. (2013). The average virial parameter for the SMC dust clouds is