Galaxies have been seen colliding before, Key to cancer drug use pinpointed ...
Naděje opens doors to relief center ... but this presents a rare example of one galaxy "attacking" another with a particle beam.

This could have a profound effect on any planets in the jet's path and could also trigger a burst of star formation.

The findings are to be published in the Astrophysical Journal.

They were obtained using Nasa's Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope, as well as the Very Large Array (VLA) and Merlin radio telescopes.

The event is occurring in a system called 3C321. It contains two galaxies in orbit around one another which are in the process of merging.

The data show that both galaxies contain supermassive black holes at their centres. But the larger galaxy - dubbed the "death star galaxy" by the astronomers - has a jet emanating from the vicinity of its black hole.

The unfortunate smaller galaxy has apparently swung into the jet's line of fire.

Destructive force

A bright spot in some images shows where the jet has slammed into the side of the galaxy, dissipating some of its energy. After striking the galaxy, the jet has become disrupted and deflected.

Jets can race out at close to the speed of light and can travel vast distances. Dan Evans said the jet in 3C321 was about 1,000 light-years across and might have travelled one or two million light-years from its origin.

These jets consist of high energy particles and magnetic fields. They produce enormous amounts of radiation, especially in the form of high-energy X-rays and gamma-rays.

"We've seen many jets produced by black holes, but this is the first time we've seen one punch into another galaxy like we're seeing here," said Dan Evans, lead author from the Harvard-Smithsonian Center for Astrophysics in Cambridge, US.

"This jet could be causing all sorts of problems for the smaller galaxy it is pummeling."

The combined effects of this radiation and particles travelling at almost the speed of light could severely damage the atmospheres of any Earth-like planets lying in the path of the jet.

For example, protective layers of ozone in the planet's upper atmosphere could be destroyed, which could result in the mass extinction of any life that had evolved on the planet.

Basic properties

"We see jets all over the Universe, but we're still struggling to understand some of their basic properties," said co-author Martin Hardcastle of the University of Hertfordshire, UK.

"This system of 3C321 gives us a chance to learn how they're affected when they slam into something - like a galaxy - and what they do after that."

The effect of the jet on the companion galaxy is likely to be substantial, because the galaxies in 3C321 are extremely close to one another. At only about 20,000 light years apart, these galaxies lie approximately the same distance as the Earth is from the centre of the Milky Way.

It is possible that it would not all be bad news for the galaxy being struck by the jet. The massive influx of energy and radiation from the jet may induce the formation of large numbers of stars and planets once its initial wake of destruction is complete.

"Although we call it a death star galaxy, it might eventually be a source of new life in the more distant galaxy," said Dr Hardcastle.

(BBC)

<< Back