Monday, December 17, 2007

Death Star Galaxy


Credit: NASA, ESA, and D. Evans (Harvard-Smithsonian Center for Astrophysics)

A powerful jet from a supermassive black hole is blasting a nearby galaxy, according to new data from NASA observatories. This never-before witnessed galactic violence may have a profound effect on planets in the jet's path and trigger a burst of star formation in its destructive wake.

Known as 3C 321, the system contains two galaxies in orbit around each other. Data from NASA's Chandra X-ray Observatory show both galaxies contain supermassive black holes at their centers, but the larger galaxy has a jet emanating from the vicinity of its black hole. The smaller galaxy apparently has swung into the path of this jet.

This "death star galaxy" was discovered through the combined efforts of both space and ground-based telescopes. NASA's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope were part of the effort. The Very Large Array (VLA) in Socorro, N.M., and the Multi-Element Radio Linked Interferometer Network (MERLIN) telescopes in the United Kingdom also were needed for the finding.

Jets from supermassive black holes produce high amounts of radiation, especially high-energy X-rays and gamma-rays, which can be lethal in large quantities. The combined effects of this radiation and particles traveling at almost the speed of light could severely damage the atmospheres of planets lying in the path of the jet. For example, protective layers of ozone in the upper atmosphere of planets could be destroyed.

Jets produced by supermassive black holes transport enormous amounts of energy far from the black holes and enable them to affect matter on scales vastly larger than the size of the black hole. Learning more about jets is a key goal for astrophysical research.

The effect of the jet on the companion galaxy is likely to be substantial, because the galaxies in 3C 321 are extremely close at a distance of only about 20,000 light-years apart, approximately the same distance as Earth is from the center of the Milky Way galaxy.

A bright spot in the VLA and MERLIN images shows where the jet has struck the side of the galaxy, dissipating some of the jet's energy. The collision disrupted and deflected the jet.

Another unique aspect of the discovery in 3C 321 is how relatively short-lived this event is on a cosmic time scale. Features seen in the VLA and Chandra images indicate that the jet began impacting the galaxy about one million years ago, a small fraction of the system's lifetime. This means that such an alignment is quite rare in the nearby universe, making 3C 321 an important opportunity to study such a phenomenon.

It is possible the event is not all bad news for the galaxy being struck by the jet. The massive influx of energy and radiation from the jet could induce the formation of large numbers of stars and planets after its initial wake of destruction is complete.

For more images and information about 3C 321, visit:
http://chandra.harvard.edu
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