Monday, October 8, 2012

1210.1802 (M. A. Latif et al.)

High resolution studies of massive primordial haloes    [PDF]

M. A. Latif, D. R. G. Schleicher, W. Schmidt, J. Niemeyer
Atomic cooling haloes with T_vir > 10^4 K are the most plausible sites for the formation of the first galaxies. In this article, we aim to study the implications of gravity driven turbulence in protogalactic haloes. By varying the resolution per Jeans length, we explore whether the turbulent cascade is resolved well enough to obtain converged results. We have performed high resolution cosmological simulations using the adaptive mesh refinement code Enzo including a subgrid-scale turbulence model to study the role of unresolved turbulence. We compared the results of three different Jeans resolutions from 16 to 64 cells. While radially averaged profiles roughly agree at different resolutions, differences in the morphology reveal that even the highest resolution employed provides no convergence. Moreover, taking into account unresolved turbulence significantly influences the morphology of a halo. We have quantified the properties of the high-density clumps in the halo. These clumps are gravitationally unbound with temperature above 6000 K and densities of the order of 10^-12 gcm^-3. In general, the clumps with SGS turbulence are denser and more massive compared with their counterparts in the standard simulation setup that ignores unresolved turbulence.
View original: http://arxiv.org/abs/1210.1802

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