Astronomers have used two Australian radio telescopes and several optical telescopes to observe a nearby radio galaxy, known as Centaurus A, and to study complex mechanisms that are fuelling jets of material blasting away from a black hole 55 million times more massive than the sun.
Centaurus A is 12 million light-years away from Earth—just down the road in astronomical terms—and is a popular target for amateur and professional astronomers in the Southern Hemisphere due to its size, elegant dust lanes, and prominent plumes of material, according to the study’s press release.
By comparing the radio and optical observations of the galaxy, the team found evidence that stars belonging to Centaurus A exist farther out than previously thought and are possibly being affected by the winds and jets emanating from the galaxy.
Several optical telescopes and observatories were involved in the study, such as the Magellan Telescope in Chile, Terroux Observatory in Canberra, Australia, and High View Observatory in Auckland, New Zealand.
“As the closest radio galaxy to Earth, Centaurus A is the perfect ‘cosmic laboratory’ to study the physical processes responsible for moving material and energy away from the galaxy’s core,” said Ben McKinley, researcher at the International Centre for Radio Astronomy Research (ICRAR) and Curtin University in Perth, Western Australia.
McKinley added that being so close to Earth and so big actually makes studying this galaxy a real challenge. He further explained that this is difficult because most of the telescopes capable of defining the details researchers need for this type of work have fields of view that are smaller than the area of sky Centaurus A takes up.
“We used the Murchison Widefield Array (MWA) and Parkes—these radio telescopes both have large fields of view, allowing them to image a large portion of sky and see all of Centaurus A at once. The MWA also has superb sensitivity allowing the large-scale structure of Centaurus A to be imaged in great detail,” McKinley said.
The MWA is a low-frequency radio telescope located at the Murchison Radio-astronomy Observatory in Western Australia, operated by Curtin University on behalf of an international consortium. The Parkes Observatory is a 64-metre radio telescope observatory, commonly known as “The Dish”, is located in New South Wales and operated by the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
Co-author of the study Steven Tingay from Curtin University and ICRAR says that “if we can figure out what’s going in Centaurus A, we can apply this knowledge to our theories and simulations for how galaxies evolve throughout the entire universe.”
“As well as the plasma that’s fuelling the large plumes of material the galaxy is famous for, we found evidence of a galactic wind that’s never been seen—this is basically a high-speed stream of particles moving away from the galaxy’s core, taking energy and material with it as it impacts the surrounding environment,” Tingay said.