Astronomers trying to find a massive black hole at the centre of the galaxy say they have finally pinpointed its location behind the thick veil of dust and gas that has kept it hidden until now. Researchers from the University of California at Los Angeles, led by Andrea Ghez, used the Keck telescope on Mauna Kea in Hawaii to measure tiny differences in infrared images of stars orbiting the estimated centre of the galaxy near a point called Sagittarius A.

Radio waves emitted by Sagittarius A make it relatively easy to find through the dust, but measuring the orbital paths of nearby stars has been difficult. The velocity, or speed of the stars, had been roughly measured, but the UCLA team took it a step further by using the infrared images of three stars to measure their acceleration - or how fast the stars were speeding up – and triangulate their center of rotation. “And the nice thing is they intersect right on top, almost exactly, of this radio source, Sagittarius A, which people have long suspected is a black hole,” said John Kormendy, an astronomer at the University of Texas in Austin. The UCLA study, published on Thursday in the journal ‘Nature’, is considered a major advance that lends support to other theories about the formation of galaxies and black holes. Bureau Report