spacetoday.net: X-ray space telescopes measure spin rate of black hole

Posted: Thu, Feb 28, 2013, 7:14 AM ET (1214 GMT)
NGC 1365 supermassive black hole illus. (NASA)

European and American space telescopes have, for the first time, measured the spin rate of a supermassive black hole in the center of a galaxy, finding evidence to support one model of how such black holes accrete matter. ESA's XMM-Newton and NASA's NuSTAR spacecraft observed the galaxy NGC 1365, looking for x-ray emission from iron atoms near the supermassive black hole at the galaxy's heart. The joint observations found that the black hole is spinning nearly as rapidly as the theory of gravity will allow. The joint observations support a model where matter flows into the black hole in a uniform matter, causing the black hole's spin rate to increase; if the matter came in irregularly and from different directions, it would rotate more slowly.