Quasar kicked out of its own galaxy in enormous event
THIS monster has been booted out of its home. So what does it take to get a supermassive black hole to run at 8 million kilometres an hour? Something even scarier?
Black holes are the top-feeding predators of the universe.
Giant black holes dominate entire galaxies.
They live in their hearts. Their immense gravity keeps every star in its place.
So when Hubble spotted one on the run in a galaxy called 3C 186, something big - very big - must have happened.
You don't simply push supermassive black holes about.
It's liable to tear you apart.
But a research paper about to be published in the journal Astronomy & Astrophysics has a good idea why.
Every galaxy has one: a supermassive black hole.
It's their anchor. Their engine. A source of destruction, and renewal.
These monsters represent the collapsed weight of more than a billion suns, producing cores so dense that their gravity governs the entire galaxy of stars orbiting them.
They're also easy for astronomers to spot: intense swirls of radiation glow around the invisible event horizon.
At this scale, these galactic overlords are called quasars.
This one has been dethroned.
Researchers pouring over Hubble photographs spotted something odd about the blurry blotch that was galaxy 3C 186.
It had the expected intense bright flare of an active quasar.
It's just that it was in the wrong spot.
The galaxy is spinning merrily along its way.
But the quasar is 35,000 light years outside its core.
"I thought we were seeing something very peculiar," study author Marco Chiaberge said in a release.
So the John Hopkins University researchers sought out as much data as they could find about the odd behaviour of 3C 186.
FINGERPRINTS OF THE GODS
The Chandra space observatory and Sloan Digital Sky Survey were co-opted to verify Hubble's strange sighting.
They peered beyond Hubble's gaze, into X-rays and the galaxy's red-shift (rate of movement away from Earth).
Like Hubble, they could not see the black hole itself. But they could also measure the size, speed and location of its superheated gas shroud.
It was real.
The clue as to why was written in the stars.
Galaxy 3C 186 bore faint scars of a colossal impact.
It's stars were bundled into vague arcs.
These are tidal-tales. Gravitational wave tsunamis imprinted upon the galaxy itself.
So what could cause this?
CLASH OF TITANS
Chiaberge's paper suggests we're observing an unusual aftermath of a clash of two galaxies.
Two intense quasars must have collided with the force of 100 million supernovas.
The quasar at the heart of Galaxy 3C 186 appears to have 'won' the duel, but at great cost.
A drawn-out interstellar wrestling match had the quasars circling each other, locked in a death struggle. The gravitational fallout of their fight lashed out among the stars around them.
3C 186 appears to have swallowed its opposing quasar, but the gravitational wrestling match unseated the victor
The paper argues that if one supermassive black hole was smaller than the other, their one-sided wrestling mach may have spun weaker gravitational waves out in one direction than the other.
Once the weakest was swallowed, the survivor would have suffered a 'recoil'.
The intergalactic judo-move toppled the victorious quasar in the opposite direction.
"This asymmetry depends on properties such as the mass and the relative orientation of the back holes' rotation axes before the merger," co-author Colin Norman writes. "That's why these objects are so rare."
Ultimately, the 3C 186 quasar's victory will be a hollow one.
It has been propelled beyond escape velocity.
In 20 million years it will pass beyond the outer rim of its family of stars, doomed to wander the universe alone.
Unless it finds another galaxy to muscle-in on.