Astronomy: Gravitational lens gives better close-ups of black hole's "jets"

Science News said:

Astronomers have caught their best look ever at blobs of hot gas fleeing a supermassive black hole, thanks to a new kind of cosmic magnifying glass.

Anthony Readhead of the Owens Valley Radio Observatory at Caltech and colleagues caught two small, hot bursts traveling away from a bright galaxy called J1415+1320 at near the speed of light. Although the galaxy is billions of light-years away and the blobs are tiny compared with the galaxy, it appears that a lucky alignment of stars may have created what’s called a gravitational lens, magnifying the galaxy and its environs.

“We’re peering right down into the core of the nucleus of this active galaxy,” Readhead says. “We think this is potentially a very powerful new window.” The researchers report their findings August 20 in two papers in the Astrophysical Journal.

J1415+1320 is what’s known as a blazar, a bright galaxy with a gluttonous supermassive black hole at its center (SN: 3/4/17, p. 13). The black hole is actively feeding on a disk of white-hot gas that swirls around it, making the host galaxy glow brightly in gamma and radio waves. The galaxy is among about 1,800 blazars that Readhead and his team have observed twice a week since 2008. “Nobody has looked at the sky quite like that before,” he says.

Starting in 2009, J1415+1320 started doing something extremely strange. Over the course of about a year, the blazar grew brighter, then dimmer, then brighter again. Plotting its brightness over time revealed a symmetrical U shape in the data.

At first, the team thought the change was caused by a cloud of plasma within the Milky Way that happened to pass between Earth and the blazar, scattering its light. But then the same thing happened again in 2014.

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