AAS 196th Meeting, June 2000
Session 26. The Galactic ISM: Observations and Modelling
Display, Tuesday, June 6, 2000, 10:00am-6:30pm, Empire Hall South

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[26.08] Compressional Formation of Molecular Clouds in SN Driven Supersonic Turbulence

J. Ballesteros-Paredes, M. Avillez, M.M Mac Low (Astrophysics Department, American Museum of Natural History)

We analyze dense clouds in 3D simulations of the ISM in which the turbulence is driven by supernova explosions. The simulations were done with a parallel Godunov method on an adaptive mesh. These clouds appear dense enough to form molecules on dynamical time scales. In the simulations, these molecular clouds are formed by the convergence of large scale streams on short timescales. These large scale motions are the result of the combined energy input by supernovae in the galactic disk.

We find that the molecular clouds can be disrupted and dispersed rapidly, on time scales of a few Myr, shorter than what is usually assumed. In the dynamical timescale {\cal L}/\Delta v, where {\cal L} is the characteristic length of the cloud, the relevant velocity dispersion \Delta v is that of the external gas, which is responsible for the compression and formation of the cloud. Finally, we discuss scaling (Larson's) relations of the molecular clouds in the simulations.

The author(s) of this abstract have provided an email address for comments about the abstract: javierbp@amnh.org

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