How Do Disks Survive Mergers?

Understand

We develop a physical model for how galactic disks survive and/or are destroyed in interactions.

• Based on dynamical arguments, we show gas primarily loses angular momentum to internal torques in a merger.
• Gas within some characteristic radius (a function of the orbital parameters, mass ratio, and gas fraction of the merging galaxies), will quickly lose angular momentum to the stars sharing the perturbed disk, fall to the center and be consumed in a starburst.
• A similar analysis predicts where violent relaxation of the stellar disks is efficient.