Oral Presentation

Energy balance between turbulence and gravity in simulations of molecular cloud fragmentation.

Author(s): Vianey Camacho (IRyA-UNAM), Enrique Vázquez-Semadeni (IRyA-UNAM) , Javier Ballesteros-Paredes (IRyA-UNAM), Gilberto C. Gómez (IRyA-UNAM), S. Michael Fall (Space Telescope Science Institute) , and M. Dolores Mata-Chávez (IA-UNAM)

Presenter: Vianey Camacho (Instituto de Radioastronomía y Astrofísica UNAM)

We discuss the balance between the turbulent and gravitational energies of clumps and cores appearing in a simulation of molecular cloud formation by colliding flows. In this simulation, turbulence is generated self-consitently due to various instabilities in the shocked layer between the streams. The resulting clump sample follows the generalized (virial-like) equipartition relation proposed by Keto & Myers and Heyer et al., sigma/R^1/2 ~ Sigma^1/2, where sigma is the velocity dispersion, R is the clump radius, and Sigma is its column density. Approximately half of the clumps with low column density and low mass show a significant kinetic energy excess, which however does not imply support, but rather is due to external compressive motions that are assembling these clumps. Finally, Larson's relations are recovered in clump subsamples that have roughly constant column density.