Saturday, August 21, 2010

Hub Science : Galactic Supervolcano Erupts From Black Hole

More high-res images of M87 can be found on the Chandra observatory website.
Images: X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al); Radio (NRAO/AUI/NSF/F. Owen)

Volcanic eruptions can wreak as much havoc in space as on Earth, a new image of galaxy M87 reveals. The black hole at the galaxy’s center is spewing gas and energetic particles in what researchers call a “galactic supervolcano,” and suppressing the formation of hundreds of millions of new stars.
The new photo shows clouds of gas that glow in X-ray light (blue) surrounding the galaxy from observations taken by the Chandra X-ray Observatory, and jets of radio emission (red) from observations from the Very Large Array of radio telescopes in New Mexico. Under normal circumstances, the hot gas would cool and fall toward the galaxy’s center, ultimately congealing and igniting the birth of new stars.

But in M87, which lies about 50 million light-years away, jets of energetic particles produced by the galaxy’s central black hole suppress the formation of new stars. The jets lift up the cooler gas near the center of the galaxy at supersonic speeds, producing shock waves in the galaxy’s atmosphere. These plumes of gas contain as much mass as all the gas within 12,000 light-years of the center of the galaxy cluster M87 belongs to. All that gas could have turned into hundreds of millions of stars if the cosmic volcano had given it a chance, researchers say.
The researchers compare the galactic volcano in M87 to the Icelandic volcano Eyjafjallajokull, whose eruption this spring choked the sky with great clouds of ash and grounded planes across Europe. Eyjafjallajokull’s eruption pushed pockets of hot gas through the surface lava, also producing shock waves that could be seen in the volcano’s smoke. The hot gas then rose up in the atmosphere and dragged cool, dark ash with it, much like the energetic jets produced in the black hole lift cooler gas away from the galactic center.
“This analogy shows that even though astronomical phenomena can occur in exotic settings and over vast scales, the physics can be very similar to events on Earth,” Stanford astrophysicist Aurora Simionescu, coauthor of a new study describing the cosmic eruption, said in a press release.
The analogy only goes so far, though. Evan Million, a grad student at Stanford and lead author of another study of M87’s volcanic nature, points out that losing millions of stars’ worth of gas “seems like a much worse disruption than what the airline companies on Earth had to put up with earlier this year.”

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