Hydrodynamic simulations of star formation from molecular cloud collisions

We studied the formation of stars from colliding molecular clouds by performing smoothed particle hydrodynamic (SPH) simulations of six head-on collisions between two molecular clouds with initial velocities of 0, 2, 4, 6, 8 and 10 km s-1 respectively. We identify the formation of stars in our simulations by a satisfaction of four criteria: density, overlap, velocity divergence, and binding energy criteria. The accuracy of the criteria was checked by reproducing an initial mass function (IMF) of the formed stars from a single cloud collapse. We also checked that with an increase of resolution in our simulations the mass spectrum produced populated more favorably stellar masses below 2M☉. In the collisions with initial velocities > 2 kms-1 we observe that star formation begins after the centers of each cloud have signicantly collided. Star formation is initiated earlier as the velocity of the collision increases, while slightly more stars form at lower collision velocities. We also identify 24 star clusters in each of the collisions and observe a linear relationship between the logarithm of the maximum stellar mass in the cluster and the logarithm of the host cluster mass.