KEY POINTS:
A "death star" galaxy is sending out a powerful jet of particles and magnetic radiation that is probably obliterating any possible life in its broad path, notably in a nearby galaxy, astronomers said yesterday.
They said the two galaxies appear to be merging and the disturbance in the
magnetic field caused by this movement may have awakened a dormant, supermassive black hole in one of the galaxies.
They have images of the deadly blast, spurting out from a system known as 3C321.
Data from Nasa's Chandra x-ray observatory show both galaxies have supermassive black holes at their centres, and 3C321, the larger galaxy, is emitting this stream of energy and particles. The unnamed smaller galaxy apparently has swung into the path of this jet.
The astronomers agree that both galaxies are likely to have planetary systems but nothing resembling life on any planet could survive the blast. While such jets have been seen before, this is the first time one has been observed battering another galaxy, the researchers report in the Astrophysical Journal.
"First, its enormous gamma ray radiation field is likely to destroy the ozone layer," Dr Dan Evans of the Harvard-Smithsonian Centre for Astrophysics, who led the study, told reporters in a telephone briefing.
And the magnetic field of any planet would be compressed, leaving it vulnerable to solar storms from its star.
"There are tens to hundreds of millions of stars in the path. Some of those stars almost certainly have planets," said Dr Martin Hardcastle, an astrophysicist at Britain's University of Hertfordshire.
"It's ... like a bully, a black hole bully, punching the nose of any passing galaxy," Neil deGrasse Tyson, director of the Hayden Planetarium at the American Museum of Natural History in New York, told the briefing.
There is no need to worry about this death ray hitting Earth - the galaxies are 1.4 billion light years away - a light year being the distance light travels in a year, or about 10 trillion kilometres.
Several telescopes were used to build a picture of the violent event, including the Chandra observatory, Hubble space telescope and Spitzer space telescope, as well as Earthbound observatories such as the Very Large Array telescope in New Mexico and Britain's Multi-Element Radio Linked Interferometer Network, Merlin, telescopes.
Such jets from black holes have been seen before, and they produce high amounts of radiation, especially high-energy x-rays and gamma-rays.
"In addition to that, there is high energy radiation coming out from the centre of the active galaxy. That is not the jet," Dr Evans said.
It is not clear why the larger galaxy started shooting out the rays. Dr Evans said the two galaxies appear to be in the process of a billion-year-long-merger. "They are actually doing somewhat of a dance around each other."
- REUTERS
