Published: Fri, July 12, 2019
Research | By Raquel Erickson

Pair of Supermassive Black Holes Discovered on a Collision Course

Pair of Supermassive Black Holes Discovered on a Collision Course

The analysis revealed within the analysis journal The Astrophysical Journal Letters on July 10 describe the two supermassive black holes as having 800 million times more mass than our sun.

The black holes, each of which has a mass more than 800,000,000 times that of our own Sun, could either merge together or or freeze a short distance from each other in a freakish phenomenon that astronomers call "the final parsec problem".

The astronomers selected this galaxy to prove the accepted models of low luminosity galaxies and their starving black holes. Some astronomers believe that once two supermassive black holes get shut enough together, decreasing their distance to 1 parsec (3.2 light-years), they may dance for eternity. Coincidentally, that's roughly the same amount of time the astronomers estimate the black holes will take to begin producing powerful gravitational waves. Detecting the gravitational wave background will help resolve some of the biggest unknowns in astronomy, such as how often galaxies merge and whether supermassive black hole pairs merge at all or become stuck in a near-endless waltz around each other.

The black hole at the center of NGC 3147, about 130 million light-years from Earth, is kind of in a bad way. The two black holes will continue to get closer to each other sending out huge ripples in space-time, also known as gravitational waves, which can be detected back to Earth.

"This is the first example of a close pair of such massive black holes that we've found, but there may well be additional binary black holes remaining to be discovered", said Michael Strauss, a co-author on the paper from Princeton's astrophysical sciences department, in a press release. "For everyone in black hole physics, observationally it is a lengthy-standing puzzle that we need to solve".

The black holes described in this study are a whopping 2.5 billion light-years away from Earth, meaning that 2.5 billion years have passed since the two were in the state that we now see them in.


In the present-day universe, the black holes are already emitting these gravitational waves, but even at light speed, the waves won't reach us for billions of years.

But whether the black holes crash or freeze, the near approach of two objects of such unimaginable size will be a hugely powerful phenomenon.

The gravitational waves generated by supermassive black hole pairs are outside the frequencies now observable by experiments such as LIGO and Virgo. However, this particular black hole, spotted by a team using NASA's Hubble Space Telescope, shouldn't exist.

"What's more, the galaxy's core is shooting out two unusually large plumes of gas". Astrophysicists predict this orbit tightens and the black holes merge over time.

So Hubble scientists were pretty confused and amazed when they found a black hole that would have been considered to be "starving", with disc around it.

The ESA's Marco Chiaberge added: "Without Hubble, we wouldn't have been able to see this because the black-hole region has a low luminosity".

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