Abstract
Phylogenetic methods have long been used in biology, and more recently have
been extended to other fields - for example, linguistics and technology - to
study evolutionary histories. Galaxies also have an evolutionary history, and
fall within this broad phylogenetic framework. Under the hypothesis that
chemical abundances can be used as a proxy for interstellar medium's DNA,
phylogenetic methods allow us to reconstruct hierarchical similarities and
differences among stars - essentially a tree of evolutionary relationships and
thus history. In this work, we apply phylogenetic methods to a simulated disc
galaxy obtained with a chemo-dynamical code to test the approach. We found that
at least 100 stellar particles are required to reliably portray the
evolutionary history of a selected stellar population in this simulation, and
that the overall evolutionary history is reliably preserved when the typical
uncertainties in the chemical abundances are smaller than 0.08 dex. The results
show that the shape of the trees are strongly affected by the age-metallicity
relation, as well as the star formation history of the galaxy. We found that
regions with low star formation rates produce shorter trees than regions with
high star formation rates. Our analysis demonstrates that phylogenetic methods
can shed light on the process of galaxy evolution.