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Astron. Astrophys. 360, 1096-1106 (2000)

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N-body simulations of self-gravitating gas in stationary fragmented state

B. Semelin and F. Combes

Observatoire de Paris, DEMIRM, 61 Av. de l'Observatoire, 75014 Paris, France

Received 30 September 1999 / Accepted 15 June 2000


The interstellar medium is observed in a hierarchical fractal structure over several orders of magnitude in scale. Aiming to understand the origin of this structure, we carry out numerical simulations of molecular cloud fragmentation, taking into account self-gravity, dissipation and energy input. Self-gravity is computed through a tree code, with fully or quasi periodic boundary conditions. Energy dissipation is introduced through cloud-cloud ineslatic collisions. Several schemes are tested for the energy input. It appears that energy input from galactic shear allows to achieve a stationary clumped state for the gas, avoiding final collapse. When a stationary turbulent cascade is established, it is possible to derive meaningful statistical studies on the data such as the fractal dimension of the mass distribution.

Key words: hydrodynamics – turbulence – ISM: clouds – ISM: general – ISM: kinematics and dynamics – ISM: structure

Send offprint requests to: B. Semelin (benoit.semelin@obspm.fr)

© European Southern Observatory (ESO) 2000

Online publication: August 23, 2000