A jet of gas spewing from a huge black hole has mysteriously brightened, flaring to 90 times its normal glow.
For seven years the Hubble Space Telescope has been watching the jet, which pours out of the supermassive black hole in the center of the M87 galaxy. It has photographed the strange phenomenon fading and then brightening, with a peak that even outshines M87’s brilliant core.
Scientists have dubbed the enigmatic bright blob HST-1, and are so far at a loss to explain its weird behavior.
“I did not expect the jet in M87 or any other jet powered by accretion onto a black hole to increase in brightness in the way that this jet does,” said astronomer Juan Madrid of McMaster University in Hamilton, Ontario, who conducted the Hubble study. “It grew 90 times brighter than normal. But the question is, does this happen to every single jet or active nucleus, or are we seeing some odd behavior from M87?”
Many supermassive black holes have jets of material that spray out perpendicularly from the donut-shaped ring of matter falling onto the black hole. These beams of hot gas are thought to result from magnetic field lines that are twisted by the black hole’s mass, and propel charged particles outward.
But most rays do not appear to blaze up with such extreme intensity as HST-1. Scientists aren’t sure if it is an exceptional case, or if it represents a normal event for black hole jets, which are still not very well understood. In this case, the bright knot of HST-1 is about 214 light-years from the M87 galaxy’s core…