An extended jet of cosmic material traveling near the speed of light emerges from a distant galaxy, looking quite similar to the afterburner pattern of a jet engine on Earth. This galactic jet flow is more than 2 million light-years long, at least 20 times larger than our Milky Way galaxy.

This outflow is coming from a distant quasar that formed roughly 6 billion years ago. Shining with the power of 10 trillion suns, the object is called PKS 0637-752 and is thought to be an early galaxy with a supermassive black hole in its center. As gas and dust fall into the black hole, they are spun around like water going down the drain of a bathtub. The spiraling motion accelerates charged particles like a cosmic version of the Large Hadron Collider, causing them to spew off tons of radiation.

Taken with the CSIRO Australia Telescope Compact Array radio telescope in New South Wales, Australia, this image shows off the radio wavelengths of the galactic jet. The parts that intrigue astronomers are the dot-like structures seen within the jet. These formations, known as "knots," are not very well understood but seem to represent sections of the jet separated by 160,000 to 360,000 light-years each.

The odd pattern suggests the jet is periodically turning on and off, or that some sort of shockwave within the jet is causing the knots. The latter explanation is similar to fighter jet afterburner exhaust patterns known as "shock diamonds." Astronomers are looking closely at the data they have about this object to figure out which model best explains the feature. A research paper about the structure appeared on Oct. 20 in the Astrophysical Journal Letters.

*Image: Dr Leith Godfrey, ICRAR and Dr Jim Lovell, UTas. *