By Ron Cowen
An invisible, highly energetic flash detected by a spacecraft early this week may have given astronomers their first glimpse of two neutron stars crashing together, forging a black hole at a galaxy’s edge.
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NASA’s Swift satellite detected the flash—a burst of gamma rays that lasted one-twentieth of a second—on May 9. Fifty-three seconds later, the craft slewed its X-ray telescope toward the same spot in the sky, fast enough to catch a rapidly fading afterglow. The X-ray detection marks the first time that astronomers have identified the location of a short-duration gamma-ray burst, which lasts less than 2 seconds, says Swift project scientist Neil Gehrels of NASA’s Goddard Space Flight Center in Greenbelt, Md.