CHEMO – DYNAMICAL EVOLUTION OF DISK GALAXIES, SMOOTHED PARTICLES HYDRODYNAMICS APPROACH Chemo – Dynamical SPH code

A new Chemo – Dynamical Smoothed Particle Hydrodynamic (CD – SPH) code is presented. The disk galaxy is described as a multi – fragmented gas and star system, embedded into the cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of standard SPH model. Using this model we try to describe the dynamical and chemical evolution of triaxial disk – like galaxies. It is found that such approach provides a realistic description of the process of formation, chemical and dynamical evolution of disk galaxies over the cosmological timescale. 1. The CD – SPH code and results The simplicity and numerical efficiency of the SPH method were the main reasons why we chose similar technique for the modelling of the evolution of complex, multi – fragmented triaxial protogalactic systems. We used our own modification of the hybrid N – body/SPH method (Berczik & Kravchuk, 1996b; Berczik & Kravchuk, 1996c; Berczik & Kravchuk, 1997a; Berczik, 1998), which we call as chemo – dynamical SPH (CD – SPH). The ”dark matter” and ”stars” were included into the standard SPH algorithm as the N – body collisionless system of particles, which can interact with the gas component only through the gravitation (Katz, 1992). The star formation process and supernova explosions were included into the scheme in the manner proposed by (Raiteri et al., 1996; Carraro et al., 1997) but with our own modifications.