Centaurus A Is the Brightest Nearby Source of Radio Waves

According to astronomers, Centaurus A, one of the nearest galaxies to the Milky Way, is the brightest source of radio waves as seen from Earth. They say that, if humans could see these wavelengths, then the galaxy would occupy an area of the sky equal to 20 times the apparent size of the full Moon.

One of the things that we would immediately see in radio wavelengths would be that the galaxy is in fact located right between two massive gas plumes. Each of these structures is about 1 million light-years in length.

The material is apparently ejected by the supermassive black hole at the core of Centaurus A, experts say. Both plumes were found to be emitting large amounts of radiation, Daily Galaxy reports. 

Interestingly, these plumes can also be observed in gamma-rays, despite the fact that the latter form of radiation is about 100 billion times more energetic than radio radiation is.

Astrophysicists operating the NASA Fermi Gamma-Ray Space Telescope say that they were able to detect the structures in a dataset encompassing the first ten months of operation with the observatory.

“This is something we've never seen before in gamma rays. Not only do we see the extended radio lobes, but their gamma-ray output is more than ten times greater than their radio output,” explains Fermi team member Teddy Cheung.

The expert, who is based at the Naval Research Laboratory in Washington, says that he and his colleagues would most likely have cataloged Centaurus A as a gamma-ray galaxy rather than a radio galaxy, had gamma-ray detection technologies matured before those that can pick up radio radiation.

“A hallmark of radio galaxies is the presence of huge, double-lobed radio-emitting structures around otherwise normal-looking elliptical galaxies. [Centaurus] A is a textbook example,” adds Fermi collaborator Jürgen Knödlseder.

The expert is based at the Center for the Study of Space Radiation in Toulouse, France. He adds that Centaurus A can be found some 12 million light-years away, in the constellation Centaurus.

Studies have determined that the two radio-emitting gas plumes are generated by a black hole several millions of times heavier than the Sun. When matter falls through the event horizon, some of it is accelerated at nearly the speed of light, in two opposite directions.