Never-before-seen galaxy spotted orbiting the Milky Way

New Scientist ^ | 14 Apr, 2016 | Ken Croswell

[MtnClimber]

The galaxy’s empire has a new colony. Astronomers have detected a dwarf galaxy orbiting the Milky Way whose span stretches farther than nearly all other Milky Way satellites. It may belong to a small group of galaxies that is falling into our own.

Giant galaxies like the Milky Way grew large when smaller galaxies merged, according to simulations. The simulations also suggest that whole groups of galaxies can fall into a single giant at the same time. The best examples in our cosmic neighbourhood are the Large and Small Magellanic Clouds, the Milky Way’s two brightest satellites, which probably orbit each other.

Orbiting galaxies About four dozen known galaxies orbit our own. The largest in terms of breadth is the Sagittarius dwarf, discovered in 1994 – but it’s big only because our galaxy’s gravity is ripping it apart. The next two largest are the Magellanic Clouds.

Now, Gabriel Torrealba at the University of Cambridge and his colleagues have found a new galaxy about 380,000 light years away in the constellation Crater. “It’s the fourth largest satellite of the Milky Way,” Torrealba says.

Named the Crater 2 dwarf, the new galaxy is not apparent to human eyes, though individual stars within the galaxy are visible. The team were only able to find it this January by using a computer to look for over-densities of stars in data from images taken by a telescope in Chile.

[SunkenCiv]

Thanks fieldmarshaldj, extra to APoD.

[SunkenCiv]

Thanks fieldmarshaldj.

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