alienation news

Small galaxy springs 'dark matter' surprises

In a dwarf spheroidal, found in the constellation Ursa Minor, a team of astronomers has found a clump of slow-moving stars near a galactic centre. They interpreted this clump as the remains of a group of stars known as a globular cluster.
This group of stars flies in the face of the most popular model for how dark matter is distributed in galaxies.
The 'lambda cold dark matter' model, which explains very well the large-scale structures in the Universe, predicts that dark matter rapidly increases in density towards the centre of a galaxy.
If dark matter were distributed in this way in the Ursa Minor dwarf spheroidal galaxy, the star cluster would have been dispersed. The cluster's existence shows that the dark matter is in fact distributed differently in this galaxy.