Andrew Garner

The rapid neutron-capture (r-process) element europium (Eu) is a valuable tracer of neutron star mergers and other rare nucleosynthetic events. The stellar spectroscopic survey GALAH's (GALactic Archeology with HERMES) unique wavelength range and setup include the Eu absorption feature at similar to 6645 & Aring; for almost a million stars in the most recent Data Release 4 (DR4). However, DR4 also saw a decreased precision in reported Eu measurements compared to previous data releases. In this work, we use a convolutional neural network (CNN) to perform label transfer, wherein we use the GALAH DR4 spectra and stellar parameters to infer DR3 [Eu/H] abundances. This CNN is then applied to DR4 spectra without corresponding DR3 Eu abundances to develop a new, publicly available catalogue of [Eu/H] values for high signalto-noise targets. We include [Eu/H] predictions for 118 946 stars, out of which 54 068 giants constitute our 'golden sample' of high-confidence predictions, which pass stricter quality cuts and have a reported precision