Via NASA:
If our eyes could see radio waves, the nearby galaxy Centaurus A (Cen A) would be one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. What we can’t see when looking at the galaxy in visible light is that it lies nestled between a pair of giant radio-emitting gas plumes ejected by its supersized black hole. Each plume is nearly a million light-years long.
NASA’s Fermi Gamma-Ray Space Telescope maps gamma rays, radiation that typically packs 100 billion times the energy of radio waves. Nevertheless, and to the surprise of many astrophysicists, Cen A’s plumes show up clearly in the satellite’s first 10 months of data. The study appears in Thursday’s edition of Science Express.
“This is something we’ve never seen before in gamma rays,” said Teddy Cheung, a Fermi team member at the Naval Research Laboratory in Washington. “Not only do we see the extended radio lobes, but their gamma-ray output is more than ten times greater than their radio output.” If gamma-ray telescopes had matured before their radio counterparts, astronomers would have instead classified Cen A as a “gamma-ray galaxy.”
Also known as NGC 5128, Cen A is located about 12 million light-years away in the constellation Centaurus and is one of the first celestial radio sources identified with a galaxy. “A hallmark of radio galaxies is the presence of huge, double-lobed radio-emitting structures around otherwise normal-looking elliptical galaxies,” said Jürgen Knödlseder, a Fermi collaborator at the Center for the Study of Space Radiation in Toulouse, France. “Cen A is a textbook example.”
Read the rest, here.
