History of the Star Formation Rate in the Local Disk from the G Dwarf Metallicity Distribution

Abstract

We address the question of the occurrence of star formation bursts in the solar neighbourhood by using the metallicity distribution of the G dwarfs. We present a method to recover the star formation history using simultaneously the metallicity distribution and the age-metallicity relation. The method associates the number of stars in a given metallicity interval with the corresponding time interval predicted by the age-metallicity relation. We take into account corrections relative to observational errors, cosmic scatter and scale height effects. The method is tested by simulations of the chemical evolution of a galaxy with irregular star formation rate, and our results show that it is possible to recover the star formation history fairly well. The application of the method to the solar neighbourhood shows evidences for at least two strong events of star formation: a burst 8 Gyr ago, and a lull 2-3 Gyr ago. These features confirm some previous studies on the star formation history in the local disk.