Lecture 11 Galaxy Collision Model (Toomre & Toomre)

Physics 141/241

Winter 2017

Classical Mechanics of the galactic orbits

For the initial condition, consider to separate galaxies on parabolic collision course. Galaxy A and galaxy B do not overlap initially, and the center of masses of the individual galaxies would continue on a parabolic orbit, if the interactions of the stars would not change the picture when the galaxies begin to overlap.

First, we would like to set up the appropriate initial condition for the collision as depicted in the figure above. Notes on the algorithm are given in collision orbit note. Notes on the galaxy rotations are given in Galaxy Rotations note. Examples of initial setups from previous projects are given in Table of initial conditions.

Galaxy collisions in the model of Toomre&Toomre

The classic paper Galactic Bridges and Tails (Toomre&Toomre) provides a simple physical model for the understanding of galaxy collisions. We will explore distinct collisions in the model, like: Mice, Antennae, and Cartwheel. The Midterm and the Final projects will be prepared by teams. In the Midterm projects we will apply the Toomre&Toomre model to the problems. In the Final projecst the teams will run full simulations.