Using powerful telescopes to observe nearby galaxies, astronomers have discovered one of the largest black hole jets ever seen. The jet, which measures a million light-years across from end to end, is not only massive, but is estimated to be 50 times larger than the Milky Way. Nearby galaxy NGC 2663 is nearby, only 93 million light-years away. Similar black hole jets have been spotted earlier, but the sheer size of the newfound jet and its proximity to the galaxy make it a unique find.
Astronomers at Western Sydney University observed it using ordinary telescopes and saw the elliptical shape typical of elliptical galaxies. However, they discovered something remarkable while observing the galaxy using a supertelescope called the Australian Square Kilometer Array Pathfinder (ASKAP) operated by the Commonwealth Scientific and Industrial Research Organization (CSIRO).
By analyzing radio waves recorded by the telescope, astronomers have detected a jet of material being ejected from the galaxy by the central black hole. It was found to be 50 times larger than the Milky Way, and if seen with the naked eye, it would be larger than the moon in the night sky. In the Evolutionary Map of the Universe (EMU) survey, astronomers pointed to galaxies pushing back on either side of the jet. This was found to be similar to the effect in jets.
As the exhaust plume travels through the atmosphere, ambient pressure pushes it from side to side. In turn, this causes the jet to expand and contract, making it pulsate as it travels. The pulsations appear as regular bright spots that astronomers call “shock diamonds.”
Such shock diamonds have been spotted earlier in smaller galaxy-sized jets, but this is the first time astronomers have observed massive shrinking of the jet from the side.