1. Background

1.1. Galactic Chemical Evolution

Galactic Chemical Evolution (often referred to as galactic archaeology) studies the connection between a galaxy’s evolution and the chemical compositions of its stars. Big Bang Nucleosynthesis produced only hydrogen, helium, and trace amounts of lithium, the three lightest elements on the periodic table. To first order, everything else was produced via nuclear fusion in supernovae and through various channels of stellar evolution, the yields of which are dictated by nuclear physics. The abundances of different nuclei within stars therefore has physical information on the number of nucleosynthetic events and thus the number of stars that came before it. For more theoretical background on galactic archaeology, see sections 1 and 2 and the citations therein of Johnson & Weinberg (2020).

1.2. The Singlezone Approximation

The singlezone approximation (also known as the onezone approximation, onezone models, box models, or variations thereof), refers to the assumption of instantaneous diffusion of newly produced metals in interstellar gas. This assumptions mandates that these nuclei be uniformly distributed at all times. By deliberately sacrificing all phase space information, the equations of these models reduce to a system of couple integro-differential equations of mass with time. While these equations only allow analytic solutions under further mathematical approximations, they can be easily integrated numerically.

VICE includes features for running numerical simulations of singlezone models in the singlezone class. In this documentation, we detail the analytic motivation and numerical approximations implemented in VICE in handling these simulations.