Turbulent dissipation in the interstellar medium: implications for galaxy formation and evolution

Abstract

We study turbulent dissipation in the ISM and explore some implications for galaxy formation and evolution using 2D MHD numerical simulations of compressible fluids. The turbulent kinetic energy E_k is injected by stellar sources formed self-consistently in the simulation. In the ISM-like fluid, regimes of both forced and decaying turbulence coexist. In the active turbulent regions (forced regime), E_k is dissipated locally and efficiently. In the decaying regime (far from input sources), E_k(t) decays ~(1+t)^-0.8. The residual turbulent motions may propagate distances of the order of the observed disk height, suggesting that turbulence may be the responsible of vertical support and star formation self-regulation at the disk level, but not at the level of the whole cosmological halo, as would be required in some models of galaxy formation.

3 pages, uses rmaa.cls, to appear in "Astrophysical Plasmas: Codes, Models, and Observations", Eds. J. Franco, J. Arthur, N. Brickhouse, Rev.Mex.AA Conf. Series. An error in the calculation of the dissipation time, t_d, was corrected (it referred to the dissipation in the forced regions). Now we report the global t_d, which is the relevant quantity for the whole flow