WASHINGTON: Scientists have developed a new technique of measuring the mass of supermassive black holes, which could revolutionise our understanding of how they form and help to shape galaxies.

The technique can spot the telltale tracer of carbon monoxide within the cloud of gas (mostly hydrogen) circling a supermassive black hole at the centre of a distant galaxy. By detecting the velocity of the spinning gas they are able to 'weigh' (determine the mass) of the black hole.

Detailed information on supermassive black holes, thought to be at the heart of most galaxies, is scarce: it has taken 15 years to measure the mass of just 60. The problem is that most other supermassive black holes are too far away to examine properly even with the Hubble Space Telescope.

The new method, developed by a team including Oxford University scientists, when combined with new telescopes such as ALMA (Attacama Large Millimetre/submillimetre Array), promises to extend this black hole 'weigh-in' to thousands of distant galaxies.

It will also enable the study of black holes in spiral galaxies (similar to our own Milky Way), which are hard to target using currently available techniques.

The team demonstrated the new technique on the supermassive black hole at the centre of a galaxy, NGC 4526, in the constellation of Virgo. NGC 4526 was chosen as a test because it has been widely studied but the team believe the technique will work on a wide range of different galaxies.