Comparison of the dust molecular gas masses estimated in M 83. Points with error bars are the values derived using the Herschel SPIRE FTS data. Blue points indicate the values estimated with I_{CO(1 − 0)} (X_CO = 2 × 10²⁰ cm^-2 (K km s^-1)^-1) when there is no available data from FTS observation. Red crosses indicate the values used in Foyle et al. (2012), in which the G/D is estimated to be 84 ± 4 (dashed line) within M 83.