Rare And Unusual Rectangular Galaxy Found By Astronomers

The star gazers - from Australia, Germany, Switzerland and Finland - discovered the quirky cosmic phenomenon within a group of 250 galaxies some 70 million light years away.A rare rectangular galaxy with a striking resemblance to an emerald cut diamond has been discovered by astronomers.

‘In the Universe around us, most galaxies exist in one of three forms - spheroidal, disc-like, or lumpy and irregular in appearance,’ said Associate Professor Alister Graham from Swinburne University of Technology in Australia.

Associate Professor Alister Graham said ‘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.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.’ and he added the rare rectangular-shaped galaxy was a very unusual object.

However, the astronomers suspect it is unlikely that this galaxy is actually rectangular in shape. Instead, they believe that it may resemble an inflated disc seen side on, like a short cylinder.
Support for this scenario comes from observations with the giant Keck Telescope in Hawaii, which revealed a rapidly spinning, thin disc with a side-on orientation lurking at the centre of the galaxy. The outermost measured edge of this galactic disc is rotating at a speed in excess of 100,000 kilometres per hour (62,000mph).

‘One possibility is that the galaxy may have formed out of the collision of two spiral galaxies,’ said Swinburne's Professor Duncan Forbes, co author of the research. The unusually shaped galaxy was detected in a wide field-of-view image taken with the Japanese Subaru Telescope for Swinburne astrophysicist Dr Lee Spitler, who was actually using it to look for something else.

A widely held theory is that galaxies grow via mergers, most often as bigger galaxies consume their smaller companions. In fact, our Milky Way galaxy shows signs of recent snacking on one of its dwarf companions. The rectangular galaxy is something of a hybrid, though, because it shows characteristics of two established types of galaxy mergers.

Elliptical galaxies tend to lack the ingredients for making new stars, so computer simulations show that when two ellipsoids merge, the galaxies form similar—if less extreme—boxy shapes and have little star-forming activity.

By contrast, the models show that galaxies with lots of star-forming gases don't become rectangular after they merge, but they do exhibit fresh rounds of star formation. The Subaru image, however, revealed that LEDA 074886 has both a geometric outline and an inner disk of star formation. The unusual dwarf galaxy may therefore help astronomers model more complex types of galaxy mergers.

Ben Moore, a theoretical physicist at the University of Zurich and a study co-author, already had plans to model the formation of LEDA 074886 on a supercomputer later this year. Those simulations will help determine, for example, how long the galaxy will keep its boxy shape, Graham said. In space, diamonds aren't forever: Unless LEDA 074886 merges with yet another perfectly aligned galaxy, it may lose its well-defined corners over the next billion years.