New Astrobites Post: The Milky Way Used to Have a Sister Galaxy

My newest Astrobites post is live!

This post was extra fun to write because the authors of the paper I covered work right down the hall from me in the University of Michigan Astronomy department! (No conflicts of interest though, my work has nothing to do with theirs.)

The authors compared a variety of observations of the Andromeda galaxy and its weirdly compact elliptical companion, M32, to results of simulations they had run. They found that M32 was likely much, MUCH bigger about 2 billion years ago, right before Andromeda consumed it. In fact, we now think that M32 used to be the third largest galaxy in our nearby cosmic neighborhood! Talk about a big meal (for Andromeda, that is).