A New Chemodynamical Galaxy Formation Model withRadiative Transfer

Abstract

We integrate three fundamental physical processes, i.e. star formation, structure formation,and radiative transfer inside galaxies, into our chemodynamical model. Our model simulates dynamical evolution in N-body SPH method, and simulates star formation as well as radiative gas cooling, feedback processes from stellar wind and supernovae. Furthermore, we implement radiative transfer in the galaxy so that we can simulate gas photoionization heating by ultraviolet (UV) photons emitted by OB stars inside the galaxy, and so that we can obtain the whole spectral energydistribution after dust absorption without assumption on dust, gas and stellar geometry, even if the simulated galaxy has very irregular morphology. We simulate seven galaxies. Our model galaxies with photoionization by UV photons show two differences from model galaxies without them. UV photons invoke gas outflow from the system, and result in smaller star formation rate at z < 1. Our simulated galaxies successfully reproduce star formation rate and density profile of nearby elliptical galaxies. Comparison with recent observations on high redshift galaxy populations suggests the following evolutionary paths. In our main model, simulated galaxy becomes LBG at z = 4.5 and 3.0 > z > 2.8, and satisfies the criteria of BzK at 3.0 > z > 2.0. Then the model galaxy enters into the short passively evolving ERO phase at z = 1.6 and finally evolves to a passively evolving elliptical galaxy. In all our simulations, evolutionary path from LBGs at z = 4, through the BzK phase at 3 > z > 1.8, to passively evolving elliptical galaxies at z < 0.8, are universal.