Comparison of methods used to derive the Galactic star formation history from white dwarf samples

ABSTRACT We compare three methods of deriving the local Galactic star formation history, using as a benchmark the Gaia-defined 40 pc white dwarf sample, currently the largest volume complete sample of stellar remnants with medium-resolution spectroscopy. We create a population synthesis model to (1) reproduce the observed white dwarf luminosity function, (2) reproduce the observed absolute Gaia G magnitude distribution, and (3) directly calculate the ages of all individual white dwarfs in the 40 pc volume. We then compare the star formation histories determined from each method. Previous studies using these methods were based on different white dwarf samples, and as such, were difficult to compare. Uncertainties in each method, such as the initial mass function, initial–final mass relation, main-sequence lifetimes, stellar metallicity, white dwarf cooling ages and binary evolution, are accounted for to estimate the precision and accuracy of each method. We conclude that no method is quantitatively better at determining the star formation history, and all three produce star formation histories that agree within uncertainties of current external astrophysical relations.