An international team of astronomers using the CSIRO Australia Telescope Compact Array radio telescope in New South Wales has captured an image of a supersonic jet of material that blasts over two million lights years from the center of a distant galaxy, and looks strikingly similar to the afterburner flow of a fighter jet.
“One intriguing possibility is that the pattern we see in this cosmic jet is produced in the same way as the pattern in the exhaust from fighter jet engines,” said Dr Leith Godfrey of the International Center for Radio Astronomy Research, lead author of a study published in the Astrophysical Journal Letters (arXiv.org version).
The new image shows the galaxy-scale jet PKS 0637-752 to have bright and dark regions, similar to the phenomenon in an afterburner exhaust called ‘shock diamonds.’
“The jets are produced when material falls onto a supermassive black hole at the center of a galaxy, but many details beyond that remain unknown. Massive jets like this one have been studied for decades, since the beginning of radio astronomy, but we still don’t understand exactly how they are produced or what they’re made of,” Dr Godfrey said.
“If the brighter patches are caused by the same process in astronomical jets as they are in earthly jet engines, then the distance between them can give us important information about the power of the jet and the density of the surrounding space. Jets like the one we studied are the largest objects in the Universe, about 100 times larger than the Milky Way.”
“If we want to understand how galaxies form and grow, we need to understand these jets. They are extremely powerful and are believed to stop stars forming in their parent galaxy, limiting how big the galaxies can grow and effecting how the Universe looks today,” Dr Godfrey said.
“This new image of the jet shows detail we’ve never seen before and the pattern we revealed provides a clue to how jets like this one work,” said study co-author Dr Jim Lovell of the University of Tasmania. “This particular jet emits a lot of X-rays, which is hard to explain with our current models. Our new find is a step forward in understanding how these giant objects emit so much X-Ray radiation, and indirectly, will help us understand how the jet came to be.”
Bibliographic information: Godfrey L.E.H. et al. 2012. Periodic Structure in the Megaparsec-scale Jet of PKS 0637–752. ApJ 758, L27; doi: 10.1088/2041-8205/758/2/L27