Q&A: Galaxies, Galaxy Clusters, AGN, and Quasars

Q:
When our Galaxy collides with the Large Magellanic Cloud, how long will it take for the starbursts to die down, assuming the mass of the Large Magellanic Cloud is 1/10 the mass of our Galaxy?

A:
We really don't know. The best studied systems are sets of 2 full galaxies which are violently colliding, such as the Antennae. A Chandra image and discussion of the Antennae collision may be found here:
http://chandra.harvard.edu/press/04_releases/press_010704.html

In these strongly interacting systems there should be a large amount of stellar formation, triggered by collisions between huge gas clouds. However, in a system such as the Milky Way and the Magellanic Clouds (Large or Small), the smaller galaxy gets torn apart by the tidal forces from the larger galaxy (in this case the Milky Way). It is not clear at the moment how much star formation activity is generated by such a collision, it may be a negligible amount. This type of collision is sometimes referred to as "galactic cannibalism."

So, the short answer is that the answer to your question is not known at this time. You may be interested in our discussion of tidal forces in the Universe, found in the following Chandra Chronicles article:
http://chandra.harvard.edu/chronicle/0104/tidal/index.html