We conclude that a galaxy’s relative size is set by the combined effects from it’s environment and halo mass.

Using a Random Forest regression model, we find that while galactic environment is significant in predicting a galaxy’s relative size, it’s halo mass plays a similarly important role.

Specifically, we look into how environment predicts deviations away from 3 key galaxy scaling relationships at fixed stellar mass.

We use the cosmological volume sim, FIREbox to study the effects of environment on galactic size and dark matter content.