Uncertainties in Galactic Chemical Evolution Models
  We use a simple one-zone galactic chemical evolution model to quantify the
uncertainties generated by the input parameters in numerical predictions, for a
galaxy with properties similar to those of the Milky Way. We compiled several
studies from the literature to gather the current constraints for our
simulations regarding the typical value and uncertainty of seven basic
parameters, which are: the lower and upper mass limits of the stellar initial
mass function (IMF), the slope of the high-mass end of the stellar IMF, the
slope of the delay-time distribution function of Type Ia supernovae (SNe Ia),
the number of SNeIa per Msun formed, the total stellar mass formed, and the
final mass of gas. We derived a probability distribution function to express
the range of likely values for every parameter, which were then included in a
Monte Carlo code to run several hundred simulations with randomly selected
input parameters. This approach enables us to analyze the predicted chemical
evolution of 16 elements in a statistical way by identifying the most probable
solutions along with their 68% and 95% confidence levels. Our results show that
the overall uncertainties are shaped by several input parameters that
individually contribute at different metallicities, and thus at different
galactic ages. The level of uncertainty then depends on the metallicity and is
different from one element to another. Among the seven input parameters
considered in this work, the slope of the IMF and the number of SNe Ia are
currently the two main sources of uncertainty.
