Backward stars point to galactic cannibalism

[Donnachaidh]

http://www.newscientist.com/article/mg21028064.100-backward-stars-point-to-galactic-cannibalism.html

STARS orbiting the wrong way in their galaxy's heart are probably the remnants of another galaxy that was eaten.

Astronomers have noted for years that the stars at the heart of some galaxies orbit in the opposite direction to that of their neighbours further out.

One suggestion has been that the stars were part of a smaller galaxy swallowed up by the host, but it was hard to find evidence to clinch the case. Now, observations by Kaj Kolja Kleineberg of La Laguna University in Tenerife, Spain, and colleagues bolster the galactic cannibalism theory.

They measured the light spectrum of stars in NGC 1700, an elliptical galaxy about 160 million light years away with a counter-rotating core. They found that the core stars appear to be younger than those in the outer regions - which would not be expected if the stars were all born in the same galaxy.

More at the link --