SIMBAD references

We have investigated collisions between clumpy molecular clouds with two-dimensional hydrodynamical simulations. We consider collisions between a typical giant molecular cloud, the GMC, and a smaller one, the SMC, both of which have disturbed clumpy structure due to internal turbulence, and follow the evolution focusing our attention on the effect of the clumpy nature of the clouds. For a given GMC, the evolution and the fate of the collision depends on the size of the SMC. If its size is small (e.g. diameter one tenth of the GMC), the SMC is able to pass through the GMC giving no serious damage to its global structure, in marked contrast with the more destructive nature of collisions between uniform clouds. In the case where the SMC is large (e.g. diameter one half of the GMC), the shocked region suffers strong perturbations due to interaction with the internal clumps and shows large distortion. The compressed SMC is finally broken into many dense gas clumps, and the GMC is seriously damaged and disrupted by the collision. In all the cases we have considered, very dense gas clumps are formed as a result of the collision. Since the mass of these clumps is well above the Jeans mass, stars will be formed triggered by the cloud collision. The results indicate that the internal clumpy structure of molecular clouds strongly affects the structure and the evolution of the colliding clouds and star formation is triggered by the cloud-cloud collision. We have compared these results with those of uniform clouds to find that the difference is very significant in the formation of dense gas clumps and the ultimate fate of the collision.