All galaxies contain stars, gas (called the interstellar matter, or ISM), and dark matter. Many galaxies exist in groups of galaxies, or clusters, and clusters are filled with a hot x-ray emitting gas (called the intercluster medium, or ICM). As galaxies live out their days, they are in orbit about the center of mass of the cluster. The gas in a galaxy can interact with the gas in the cluster and can be stripped away. This is called 'Ram Pressure Stripping', and can dramatically alter the evolutionary history of a galaxy. All movies show the log(density) for the gas distribution as a function of time for a disk galaxy passing through a rich cluster such as Coma. The simulations are performed in the frame of reference of the moving galaxy, and the flow velocity is 2000 km/s, about Mach 1.9. All simulations are fully three dimensional. We are interested in studying how quickly the gas is removed, and how much gas remains after a stripping event. These movies span a typical time scale of about 100 million years.
In the first sequence the flow is face on, and the movie shows the X-Y plane (a slice through Z, flow in the X direction).