A detailed self-consistent vertical Milky Way disc model

Abstract

We present a self-consistent vertical disc model of thin and thick disc in the solar vicinity. The model is optimized to fit the local kinematics of main sequence stars by varying the star formation history and the dynamical heating function. The star formation history and the dynamical heating function are not uniquely determined by the local kinematics alone. For four different pairs of input functions we calculate star count predictions at high galactic latitude as a function of colour. The comparison with North Galactic Pole data of SDSS/SEGUE leads to significant constraints of the local star formation history. In (2) we published a self-consistent vertical disc model of thin and thick disc in the solar cylinder. The thin disc model is based on a series of stellar subpopulations with surface densities and velocity dispersions according to an adopted star formation history (SFR) and a dynamical heating function (AVR). An isothermal thick disc component is included self-consistently. The discs are in dynamical equilibrium including the gravitational forces of the gas component and the dark matter halo. A simple chemical enrichment model is included to reproduce the metallicity distribution of the G-dwarfs in the solar neighbourhood. The SFR and AVR are varied in order to fit the local kinematics of main sequence (MS) stars and to match other constraints of the local stellar disc. We selected four models fitting the local kinematics equally well, but the SFR cannot be determined by the local kinematics alone (top panels of Fig. 1).