Astronomers spot 'emerald-cut' galaxy

Posted by Kate Taylor

Astronomers have discovered a weird rectangular galaxy within a group of 250 galaxies some 70 million light years away.

Most galaxies are spheroidal, disc-like, or lumpy and irregular in appearance - but this one looks like an emerald-cut diamond.

"It's one of those things that just makes you smile because it shouldn't exist, or rather you don't expect it to exist," says associate professor Alister Graham from Swinburne University of Technology.

"It's a little like the precarious Leaning Tower of Pisa or the discovery of some exotic new species which at first glance appears to defy the laws of nature."

The galaxy, which was discovered using the Japanese Subaru Telescope, probably isn't shaped like a cube. Instead, the team suggests it may resemble an inflated disc seen side on, like a short cylinder - a view supported by observations with the Keck Telescope in Hawaii.

"One possibility is that the galaxy may have formed out of the collision of two spiral galaxies," says Swinburne's Professor Duncan Forbes.

"While the pre-existing stars from the initial galaxies were strewn to large orbits creating the emerald cut shape, the gas sank to the mid plane where it condensed to form new stars and the disc that we have observed."

The disc-like structure is comparable with merger simulations involving star formation, says Graham.

"Curiously, if the orientation was just right, when our own disc-shaped galaxy collides with the disc-shaped Andromeda galaxy about three billion years from now we may find ourselves the inhabitants of a square looking galaxy," he says.