Can We Bridge the Gap Between Observation and Theory?

Abstract

It is important to improve methods for interpreting observations of FeII lines produced by real astronomical objects. Detailed complex calculations including a very large number of energy level (e.g. one million) are not necessarily very useful, as many assumptions about the nature of the emitting regions and their geometry are included. It is not clear what role the assumptions play, and those which might be valid for one kind of object (e.g. Active Galactic Nuclei) are not necessarily valid for others (e.g. stellar winds).