Powerful jet: This image taken in ultraviolet light by NASA's Hubble Space Telescope reveals a jet of gas blasting from the core of the gigantic elliptical galaxy M87.
Credit: NASA, ESA, and J. Madrid (McMaster University)
SYDNEY: A flare-up in a jet of matter blasting from a monster black hole is giving astronomers an incredible light show.
The outburst is coming from a blob of matter, called HST-1, embedded in the jet, which is a powerful beam of hot gas produced by a supermassive black hole residing in the core of the giant galaxy M87. M87 is located 54 million light-years away in the Virgo Cluster.
HST-1 is so bright that it is outshining even M87's brilliant core, whose supermassive black hole is one of the biggest yet discovered.
Roller coaster ride
NASA's Hubble Space Telescope has been following the surprising activity for seven years, providing a detailed ultraviolet-light view of the event. The flare-up may provide insights into the variability of black hole jets in distant galaxies, which are difficult to study because they are too far away.
The glowing gas clump has taken astronomers on a roller coaster ride of suspense. Astronomers watched HST-1 brighten steadily for several years, then fade, and then brighten again. They say it's hard to predict what will happen next.
The light show is detailed this month in The Astronomical Journal.
Study co-author and astronomer Juan Madrid, of McMaster University in Ontario, Canada, said he didn't expect the jet in M87 to increase in brightness this way.
Mysterious effect
"It grew 90 times brighter than normal," he said. "But the question is, does this happen to every single jet or active nucleus, or are we seeing some odd behaviour from M87?"
Despite many observations by Hubble and other telescopes, the astronomers are not sure what is causing the brightening.
One of the simplest explanations could be that the jet is hitting a dust or gas cloud and glowing due to the collision. Another possibility is that the jet's magnetic field lines are squeezed together, unleashing energy. This phenomenon would be similar to how solar flares develop on the Sun, says Madrid.
