| The purpose of this thesis is to investigate the validity of the cold dark matter (CDM) model by comparing the predictions of large-scale hydrodynamic simulations with variety of available astronomical data on galaxies. The simulations we use include a heuristic star formation recipe which allows us to study galaxy formation without making any ad hoc assumptions on the bias of galaxy distribution relative to underlying dark matter distribution. Our simulation also have additional unique features of self-consistent treatment of supernovae feedback, ultra-violet radiation field, radiation shielding, metal enrichment and metal cooling. Furthermore, a population synthesis model is used to make predictions in terms of observable light. Firstly, we discuss star formation history, stellar metallicity distribution, mass function, luminosity function, and colors of galaxies in a ΛCDM universe, both in the local universe and as functions of time. Secondly, we study the evolution of Lyman Break Galaxies at redshift 3, with particular emphasis on their star formation history, merger history, and metallicity distribution. Finally, the cosmic Mach number and its environmental dependence on overdensity and galaxy mass and age is studied. The overall picture is that there is an impressive, though imperfect match between theory, numerical simulations, and observations. |
