Hubble rings a black hole

The Hubble Space Telescope's latest picture is of swirling gas surrounding a black hole at the core of a distant galaxy.

The spiral galaxy lies 13 million light-years away in the southern constellation Circinus.

Astronomers say that much of the gas in the disc of the Circinus spiral is concentrated in two rings. The largest has a diameter 1,300 light-years and has already been observed. But Hubble has picked out a previously unseen ring with a diameter of 260 light-years.

A light year is the distance light will travel in one year and is about nine-and-a-half million, million kilometres (six million, million miles).

Starburst

In the Hubble image, the smaller inner ring is located on the inside of the green disc. The larger outer ring extends off the image and is in the plane of the galaxy's disc.

Both rings contain large amounts of gas and dust as well as areas of "starburst" activity, where new stars are rapidly forming. At the centre of the starburst rings is believed to be a supermassive black hole that is accumulating the surrounding gas and dust.

Gas is also being expelled from the violent region around the black hole. The detailed structure of this gas is seen as magenta-coloured streamers extending towards the top of the image.

In the centre, within the inner starburst ring is a v-shaped structure of gas. This region contains gas that has been heated by radiation emitted from the area immediately around the black hole.

Located beyond the far side of our Milky Way Galaxy, the Circinus galaxy is partially hidden by intervening dust along our line of sight. As a result, the galaxy went unnoticed until about 25 years ago.