Friday, March 24, 2017

Gravitational Waves Push Supermassive Black Hole Out Of Galaxy's Center

An international team of astronomers using NASA's Hubble Space Telescope have uncovered a supermassive black hole that has been propelled out of the center of the distant galaxy 3C186 by what could be the awesome power of gravitational waves.

Though several other suspected runaway black holes have been seen elsewhere, none has been confirmed so far. Astronomers think this object, detected by NASA's Hubble Space Telescope, is a very strong case. Weighing more than 1 billion suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home.

Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.

First predicted by Albert Einstein, gravitational waves are ripples in space that are created when two massive objects collide. The ripples are similar to the concentric circles produced when a hefty rock is thrown into a pond. Last year, the Laser Interferometer Gravitational-Wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar-mass black holes, which are several times more massive than the sun.

Hubble's observations of the wayward black hole surprised the research team. "When I first saw this, I thought we were seeing something very peculiar," said team leader Marco Chiaberge of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland.

"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."

ABOVE IMAGE: The illustration shows how gravitational waves can propel a black hole from the center of a galaxy. 

1. The scenario begins in the first panel with the merger of two galaxies, each with a central black hole. 

2. In the second panel, the two black holes in the newly merged galaxy settle into the center and begin whirling around each other. This energetic action produces gravitational waves. 

3, As the two hefty objects continue to radiate away gravitational energy, they move closer to each other over time, as seen in the third panel. If the black holes do not have the same mass and rotation rate, they emit gravitational waves more strongly in one direction, as shown by the bright area at upper left. 

4. The black holes finally merge in the fourth panel, forming one giant black hole. The energy emitted by the merger propels the black hole away from the center in the opposite direction of the strongest gravitational waves.

Image Credit and article source: NASA/ESA