Accurate prediction of post-merger galaxy properties

Determine whether the post-merger properties of galaxies can be accurately predicted from arbitrary pre-merger conditions, including the physical factors responsible for outlier merger outcomes.

Background

The study identifies collision angle, cold gas fraction, and pre-merger morphology as the principal factors associated with post-merger morphology in the TNG100-1 simulation. However, the authors emphasize that these statistical trends do not provide a reliable event-by-event predictive model. Some cold gas-rich spiral-in mergers produce elliptical-like remnants, while some cold gas-poor head-on mergers yield disk galaxies, indicating that additional physical factors may influence individual outcomes.

The unresolved problem is therefore to establish whether, and by what means, post-merger galaxy properties can be accurately predicted from specified pre-merger conditions rather than only characterized through population-level correlations.