Astronomers mapped out an elliptical galaxy an estimated 500 million light-years from Earth that spews out two beams of high energy gamma rays. Images from the National Science Foundation’s Very Long Baseline Array show the rays traveling in opposite directions and producing two lobes of light on either side of the galaxy’s bright core, reminiscent of one of the starships often seen in Star Wars movies.
“The first time I saw the results, I immediately thought it looked like Darth Vader’s TIE fighter spacecraft,” said Matthew Lister, a professor of physics and astronomy at Purdue University. “That was a fun surprise.”
Lister’s paper in The Astrophysical Journal on Aug. 25 explained how astronomers about 90 years ago observed the galaxy beginning to eject jets of material from its core at about one-third the speed of light. The jets collided with other material, stopped, and flowed back toward the galaxy’s center, creating lobes filled with fast-moving particles spiraling around magnetic fields. About 50 years ago, the jets stopped, leaving the glowing lobes behind before starting again about a decade ago.
Astronomers classify the galaxy as active because all of its stars together cannot produce the total amount of light it emits. The extra energy comes from radio waves, X-rays, and gamma rays. Only about one-tenth of active galaxies produce bright lobes.
Scientists think this galaxy’s emissions originate from regions near the supermassive black hole at its center that is about 1 million times as dense as our sun. Near the black hole, friction and gravity cause a hot, swirling disc of gas and dust. —J.B.