Astronomers have watched the sudden brightening of a galaxy and realized it can mean only one thing: a supermassive black hole has “woken up” and feasted after a long period of hibernation. Technically, though, the black hole was always ‘awake’; a large planetary body actually drifted too close and felt the behemoth’s gravitational wrath. That’s what you get for “playing chicken” with an event horizon, I suppose.
ANALYSIS: Our Galaxy’s Black Hole Has the ‘Munchies’
The discovery was made by the European INTEGRAL space observatory that keeps an eye on the Cosmos for high-energy gamma-rays and X-rays. While carrying out a study on a different galaxy, INTEGRAL — which stands for INTErnational Gamma-Ray Astrophysics Laboratory — spotted a surprise brightening of NGC 4845, a spiral galaxy some 47 million light-years away. Follow-up observations by ESA’s XMM-Newton, NASA’s Swift and Japan’s MAXI X-ray monitor on the International Space Station confirmed that, despite decades of silence, NGC 4845 just ate a big dinner.
The X-ray brightening reached a peak in January 2011 and then slowly subsided over the course of a year.
“The observation was completely unexpected, from a galaxy that has been quiet for at least 20–30 years,” said Marek Nikolajuk of the University of Bialystok, Poland, lead author of the research published in the journal Astronomy & Astrophysics.
By analyzing the energy of the emissions and the period of time the “feeding” lasted, astronomers were able to calculate the mass of the black hole’s meal. An object with a mass of 14-30 Jupiters had strayed too close, gotten ripped to shreds and formed a short-lived accretion disk around the black hole’s event horizon. This mass is consistent with a large planet or small brown dwarf being eaten alive. The matter then spiraled into the black hole, generating massive quantities of radiation in the process.
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This portrait looking down on Saturn and its rings was created from images obtained by NASA's Cassini spacecraft on Oct. 10, 2013. It was made by amateur image processor and Cassini fan Gordan Ugarkovic. This image has not been geometrically corrected for shifts in the spacecraft perspective and still has some camera artifacts.The mosaic was created from 12 image footprints with red, blue and green filters from Cassini's imaging science subsystem. Ugarkovic used full color sets for 11 of the footprints and red and blue images for one footprint.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
Earth seen from Mars. Mars seen from Earth. Left: Earth and its moon in the evening sky of Mars, as seen by the Curiosity rover. Right: Mars rising over Salt Lake City. Mars credit: NASA/JPL-Caltech/MSSS/TAMU. Earth credit: Bill Dunford.