The Sagittarius Dwarf Elliptical Galaxy
5 years ago, astronomers found a new galaxy in the direction of Sagittarius.. It's currently colliding with our Milky Way galaxy! It was found based on the "streaming motions" of an enormous group of stars. Two globular clusters, which had never quite fit the characteristics of other globular clusters in our own galaxy, have now been found to be from the Sagittarius dwarf galaxy.
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An image of SagDEG. It's clear to see why this dwarf galaxy was so difficult to find! How many of our halo and bulge stars came from such mergers? It is thought maybe 8-10%.. |