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S. C. O. Glover, M.-M. Mac Low (American Museum of Natural History), M. D. Smith, G. Pavlovski, A. Rosen (Armagh Observatory, Northern Ireland)
Chemical and dynamical simulations of molecular clouds generally assume that the gas is perfectly isothermal. However, it is not clear that this approximation is always appropriate; supersonically turbulent gas will inevitably deviate from isothermality to some degree due to intermittent shock heating, but the extent of these deviations and their effects on the dynamical evolution and observational properties of molecular clouds have so far attracted little study.
To investigate the significance of this non-isothermal behaviour, we have begun a series of simulations of driven turbulence in molecular gas using the ZEUS-MP code together with a detailed molecular cooling function and a simplified treatment of molecular chemistry in place of the usual isothermal approximation. We present preliminary results from this study, from simulations with resolutions of 643, 1283 and 2563. We examine how important features of the turbulent flow, such as the kinetic energy dissipation rate, or the density and pressure PDFs, differ from those obtained from analogous isothermal simulations. We also characterize the dominant coolants of the gas and investigate the potential detectability of the resulting emission.
This work has been supported by NSF grants AST99-85392 & AST-0307793 and by NASA Education Grant NAG-5-13028.
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.