SIMULATION OF STAR FORMATIONS IN COSMOLOGICAL VOLUME (240 Mpc/h)^3

In this paper the Lambda Cold Dark Matter (ΛCDM) model was used for studying star formation inside a box of size (240Mpc/h)^3 by simulating eight million dark matter particles and eight million gas particles together with cosmological density Ω=0.25, dark energy density ΩΛ=0.75, baryon density Ωb=0.04, fluctuation amplitude σ8=0.9 and Hubble constant H0=100h kms^-1Mpc^-1. The gadget-2 code was used for simulating the particles from early Universe, z=30 (450 million years) to z=0 (13.4 billion years). In the box the structures formation were shown including galaxy clusters, voids and filaments which observed clearly at low redshift, z=0. In the temperature-density planes, the thermal processes of cooled gas show the density and temperature values which were different at each redshift, and the gas cooled in the box at nearly 10^4K caused star formations at certain redshifts. It was also found that stars were formed from z=7.3 which increased with decreasing redshifts. In addition, the total number of star formed in the box was 226217 stars. Sixteen processors of high performance supercomputer of Nottingham University-England were used in the simulation.