X-ray pulse detected near event horizon as black hole devours star
On Nov. 22, 2014, astronomers spotted a rare event in the night sky: A supermassive black hole at the center of a galaxy, nearly 300 million light-years from Earth, ripping apart a passing star. The event, known as a tidal disruption flare, for the black hole’s massive tidal pull that tears a star apart, created a burst of X-ray activity near the center of the galaxy. Since then, a host of observatories have trained their sights on the event, in hopes of learning more about how black holes feed. Now researchers at MIT and elsewhere have pored through data from multiple telescopes’ observations of the event, and discovered a curiously intense, stable, and periodic pulse, or signal, of X-rays, across all datasets. The signal appears to emanate from an area very close to the black hole’s event horizon — the point beyond which material is swallowed inescapably by the black hole....