Structure Function Scaling in the Taurus and Perseus Molecular Cloud Complexes

We compute the structure function scaling of the integrated intensity images of two J = 1-0 13CO maps of Taurus and Perseus. The scaling exponents of the structure functions, normalized to the third order, follow the velocity scaling of supersonic turbulence, suggesting that turbulence plays an important role in the fragmentation of cold interstellar clouds. The data also allow one to verify the validity of the two basic assumptions of the hierarchical symmetry model, originally proposed for the derivation of the velocity structure function scaling. This shows that the same hierarchical symmetry holds for the projected density field of old interstellar clouds.