Towards Automatic Model Atoms from the VALD Atomic Database: from He to U

Sammanfattning: The ejecta following the collision and merging of two neutron stars (kilonova) are currently considered promising sites for nucleosynthesis of r-process elements. Since the observed kilonova in 2017, GW2017817, astrophysicists have been working to analyze the collected electromagnetic spectra, trying to identify r-process elements. However, a lack of fundamental atomic data has been holding the efforts back. Motivated by spectral modelling of kilonovae out of equilibrium, this project aims to create a tool that uses line lists of spectroscopic accuracy from the Vienna Atomic Line Database (VALD) to generate energy level lists automatically for any ion. VALD in particular is used because it has wavelengths accurate enough for line identification purposes. The resulting level lists are compared to equivalent level lists from the database managed by the National Institute for Standards and Technology (NIST), in order to both ensure that the tool worked, and identify discrepancies between the databases. A number of problems with the VALD data were identified, mostly resulting in duplicate and missing energy levels. Finally, we also test the data in computations of kilonova expansion opacities in a complete solar r-process abundance mixture. Further work is needed to evaluate how damaging these problems are when modelling kilonovae, and when necessary remedy said problems.