Red light for exploding galaxy

M82: A galaxy racked by stellar explosions

By BBC News Online science editor Dr David Whitehouse

The first images from a newly commissioned telescope instrument have unveiled some of the sky's most remarkable sights.

One such feature is galaxy M82, an "active galaxy" once thought to have been shaken by a massive explosion at its core. Astronomers now believe that its strange filaments are caused by exploding stars.

The bluish band running through the image is due to light from stars in M82, which is about 12 million light-years from the Earth. The red filamentary features are the rosy glow of ionised hydrogen gas.

The filaments extend for over 10,000 light years in each direction from the centre of the galaxy.

First light

This image was produced using the Japanese Subaru Telescope's Faint Object Camera and Spectrograph (Focas) on its first night of operation in February.

Up until the early 1960s, it was believed that the glowing hydrogen gas resulted from a single massive explosion at the centre of M82. Later, however, large clouds of hydrogen gas and many remnants of exploded stars were discovered at the centre of this galaxy.

Further observations showed that the gas was flowing outwards from the nucleus of M82. It is now thought that this outflow is being driven by a so-called "starburst".

Exploded stars also combine to produce a "superwind" that blows material away from the galaxy.