Developed by a team that included Oxford University scientists, the measurement technique can spot the telltale trace of carbon monoxide within the cloud of gas circling a supermassive black hole at the center of a distant galaxy, and by detecting the velocity of the spinning gas it can determine the mass of the black hole.
Such data on supermassive black holes, assumed to be at the heart of most galaxies, are hard to come by, the researchers said; it has taken 15 years to measure the mass of just 60.
And most other supermassive black holes are too far away to examine properly even with the Hubble Space Telescope, they said.
The new technique offers the possibility of extending the "weigh-in" of black holes to thousands of distant galaxies, an Oxford release said Friday.
"Because of the limitations of existing telescopes and techniques we had run out of galaxies with supermassive black holes to observe," Oxford physicist Michele Cappellari said.
"Now with this new technique ... we will be able to examine the relationship between thousands of more distant galaxies and their black holes giving us an insight into how galaxies and black holes co-evolve."