HYDRODYNAMICAL CODE FOR NUMERICAL SIMULATION OF THE GAS COMPONENTS OF COLLIDING GALAXIES

In this paper, a new hydrodynamical code for the numerical simulation of the collision of the gas components of galaxies is described. The code is based on the Fluids-in-Cells method with the Godunov-type scheme at the Eulerian stage. Also, the velocity correction is employed at the Lagrangian stage and energy imbalance is minimized. The performance of the code is shown by the simulation of the collision of gas components of two similar disk galaxies in the course of the central collision of the galaxies in the polar direction. As a result of the numerical simulations within the model, we succeeded in determining the main scenarios of the collision of galaxies. At low velocities, both galaxies and their gas components coalesce. At high velocities, the massive stellar components of galaxies dissipate almost freely, leaving their gaseous components slowed down and heated by the collision. If the common gas component of the colliding galaxies cools down to the virial temperature, a new galaxy is formed from the two. With the high collision velocity, the gas component has no time to cool and therefore the gas dissipates in the intergalactic medium.