Black hole's feeding frenzy
2008-04-16 07:25
Paris - A black hole slumbering at the centre of our galaxy went into a "feeding frenzy" three centuries ago, the European Space Agency (ESA) said on Tuesday.
Located around 26 000 light years from Earth, the black hole, known as Sagittarius A-star (Sgr A*), is a monster with a mass four million times that of the sun.
Japanese astronomers, using ESA's XMM-Newton orbital telescope and US and Japanese X-ray satellites, discovered that clouds of gas brightened and faded in X-ray light when they passed near Sgr A*'s maw, ESA said.
The phenomenon is due to X-ray pulses that are believed to be residual bursts from a flare that happened 300 years ago.
"We have wondered why the Milky Way's black hole appears to be a slumbering giant," team leader Tatsuya Inui of Kyoto University said.
"But now we realise that the black hole was far more active in the past. Perhaps it's just resting after a major outburst."
One theory is that a few centuries ago, the powerful gravitational pull of the black hole engulfed clouds of gas from an exploding star called a supernova, ESA said.
The "temporary feeding frenzy" caused X-ray energy to leap from its mouth in a giant flare.