Gravitational Waves Push Supermassive Black Hole Out Of Its Host Galaxy

Gravitational Waves Push Supermassive Black Hole Out Of Its Host Galaxy

Black holes are known to have so much mass that it’s impossible for any light to escape through them. That’s even truer when it comes to supermassive black holes, which, as their name implies, are much more formidable than their ordinary counterparts. But NASA was able to make a rather peculiar discovery, having observed how gravitational waves seemingly kicked a supermassive black hole out of the center of its host galaxy.

NASA’s press release states that it might not be exactly a unique situation – there may have been other black holes of a similar size kicked out of their galaxy by gravitational waves. But based on what astronomers have seen on the space agency’s Hubble Space Telescope, it’s likely that they may have seen a supermassive black hole go rogue thanks to those waves. The black hole is estimated to weigh over a billion suns, and is believed to be the most massive of its kind to be booted out of its central galaxy.

The rogue black hole’s host galaxy is located about 8 billion light-years away from Earth, and wasn’t specifically named in the NASA press release. According to the Washington Post, the black hole is now believed to be moving through space at a fantastic speed of about 5 million miles-per-hour.

Lead researcher Marco Chiaberge, of the Space Telescope Science Institute and Johns Hopkins University, was quoted by NASA as saying the new findings proved to be quite a surprise, and “very peculiar” in a number of ways. For one, the quasar, or the nucleus of the galaxy, was located 35,000 light-years away from the galaxy’s center; this quasar was given the codename 3C 186.

“When we combined observations from Hubble, the Chandra X-ray Observatory, and the Sloan Digital Sky Survey, it all pointed towards the same scenario. The amount of data we collected, from X-rays to ultraviolet to near-infrared light, is definitely larger than for any of the other candidate rogue black holes.”

According to the Laser Interferometer Gravitational Wave Observatory (LIGO) page on Caltech’s official website, gravitational waves were first predicted in 1916 as part of Albert Einstein’s now-iconic theory of relativity. These are “ripples” in the space-time fabric “caused by some of the most violent and energetic processes in the universe,” and could emanate from black holes or other similarly massive objects that could accelerate through the universe at a rapid pace. The gravitational wave phenomenon was confirmed in 2016 in a groundbreaking discovery by LIGO researchers, as they were able to see the waves generated when two black holes merged.

Chiaberge and his fellow researchers believe that the gravitational waves that kicked out the supermassive black hole from its host galaxy may have come from a similar merger of massive black holes. This was gleaned from the discovery of tidal tails, which appear when two colliding galaxies produce a gravitational tug.

The aftermath of the galaxy collision, however, remains largely unknown, the Washington Post wrote. Chiaberge’s team believes that when the two galaxies collided, their black holes proceeded to circle each other, each of them generating gravitational waves. If the two black holes didn’t have matching masses and spin rates, that might have resulted in one side getting more waves than the other side. After that, the newly-merged supermassive black hole would have been sent careening in the opposite direction.

“This asymmetry depends on properties such as the mass and the relative orientation of the (black holes’) rotation axes before the merger,” explained study co-author Colin Norman, also of STScI and Johns Hopkins. “That’s why these objects are so rare.”

For an alternate explanation of why the supermassive black hole got kicked out by gravitational waves, Chiaberge and colleagues believe that the 3C 186 may have been behind its host, and not located within it. This would explain the peculiar lack of centering of the galaxy’s nucleus, but would also suggest the detection of the 3C 186’s host galaxy, which is something the researchers weren’t able to discover in their study.

[Featured Image by NASA]