Astronomers Just Found The Closest Pair of Supermassive Black Holes Ever Detected

Just 89 million light-years away, in the galaxy NGC 7727, two supermassive black holes are destined to become one.

New measurements that probe the heart of the galaxy have found that the nucleus consists of a binary supermassive black hole pair. It's the closest such binary we have found to date, beating out the previous record-holder of 470 million light-years by a significant margin.

Moreover, the two supermassive black holes are closer to each other than any other supermassive black hole binary we've seen, separated by a distance of just 1,600 light-years. Eventually, astronomers believe, the two black holes will grow so close together that they'll merge, becoming one much larger beast.

The discovery not only confirms that NGC 7727 is the product of a merger between two galaxies, but gives us a wonderfully close laboratory for probing the interactions between supermassive black holes as they whirl about in their orbital pre-merger dance.

"It is the first time we find two supermassive black holes that are this close to each other, less than half the separation of the previous record holder," says astronomer Karina Voggel of the Strasbourg Observatory in France.

There are multiple reasons why supermassive black hole binaries are of interest to astronomers. Supermassive black holes are found at the centers of most galaxies, the nuclei around which everything else whirls.

When two are found together, it indicates that two galaxies have come together. We know this process occurs; finding a supermassive black hole binary can tell us what it looks like in the final stages.

Supermassive black hole binaries can also tell us something about how these colossal objects – millions to billions of times the mass of the Sun – can get so incredibly massive. Binary black hole mergers are one way this growth can occur. Finding binary supermassive black holes will help us understand if it's a common pathway for this growth, which in turn will allow for more accurate modeling.

NGC 7727 had been an object of interest for a binary supermassive black hole for some time. Its physical characteristics suggest that the galaxy is the product of a galactic merger, sometime in its distant past. However, black holes are hard to see unless they're actively accreting material. Then, the cloud of material around the black hole shines brightly with radiation. NGC 7727 did not have the bright flow usually associated with two active supermassive black holes.

This is where the galaxy's proximity gave astronomers an edge. Because NGC 7727 is so close, the researchers were able to obtain motion data for stars in the galactic center, based on the way their light changes as they whirl around. This revealed that the galactic center contains not one, but two supermassive black holes.

One of those supermassive black holes is relatively large, clocking in at around 154 million times the mass of the Sun. The other, much smaller, companion is only 6.3 million solar masses. Only one of these black holes was found to be active: the smaller one. This explains why there was so little radiation; the much larger black hole is quiescent.

This suggests, the researchers said, that there could be many more supermassive black hole binaries out there than we can currently detect.

"Our finding implies that there might be many more of these relics of galaxy mergers out there and they may contain many hidden massive black holes that still wait to be found," Voggel said.

"It could increase the total number of supermassive black holes known in the local Universe by 30 percent."

Although the two black holes are destined to merge, it's going to take some time; around 250 million years or so, the researchers said. But, while we won't be able to observe it happening, the binary system offers hope that there are many more supermassive black hole mergers taking place around us.

We can't detect them just yet; the gravitational waves emitted would be too low frequency for our current instruments. But new instruments, such as the space-based gravitational wave detector LISA, should be able to, the researchers said.

And the discovery could tell us how to find binary supermassive black holes, even in more distant galaxies, where we can't obtain detailed motion data for the central stars.

"Targeting bright surviving nuclear star clusters in merged galaxies can facilitate the discovery of dual supermassive black holes at smaller separations in the Local Universe even when they are not luminous active galactic nuclei," they wrote in their paper.

"This will allow much more detailed studies of these systems that then can serve as blueprints of how to find them more broadly in the distant Universe."

"There are multiple reasons why supermassive black hole binaries are of interest to astronomers."

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Yes, but shouldn't the astronomers have first cleared this story with the psychology department at Berkeley? I mean there is no such thing as BINARIES anymore :- ) Did they miss the message about 58 legal genders being recognized in San Fran? /s

More seriously... Don't you love how these astrologers beef up the story about what's happening 87 million light years away as if it's a local news story? Such predictive certainty! Such faith in their own models! Alas, it's all worth it, because it makes for a great STORY!

It reminds me of the 2013 prediction of climatologists for the number of Atlantic hurricanes that year. Seven climatology organizations (NOAA, CSU, etc.) made 12 predictions and forecasted an average of 8 hurricanes, yet the seasonal total was only 2. Those experts also predicted there would be 4 major hurricanes, but by the end of the season, there were zero major hurricanes in 2013.

Seriously folks, the U.S. climate organizations should be privatized. Let these "geniuses" compete for funding with private firms -- including scientists working out of their garages. May the best hurricane modelers and AI/big data scientists win in the quest for predictive progress.

Or admit to us there are massive black holes in the quality and quantity of climate sensor data and their counting of Brazilian butterfly flaps. Tell us honestly that we are currently light years away from accurate climate predicting.

LOL, that was good..."black hole" and "binaries" both racist and sexist in one fell swoop!

As for the weather...my wife and I went to a lecture at the Boston Museum of Science back in the Nineties, and the lecturer was from the National Weather Service, and he told us that within five years, they would be able to accurately predict weather down to the city block size up to a month out!

I remember hearing that back then, and I think I may have had to stifle and terminate a involuntary snort of disbelief! I had to laugh, it made me think of this account of an exchange a couple of years back with Bill Belichick (NFL coach of the Patriots):

With current forecasts leaning toward a snowy weekend, reporters at Friday's presser asked Belichick about the weather and how it would affect Sunday's game vs. the Denver Broncos. His stance on the weather forecast for fell somewhere between a hot weather take and a cold shoulder to meteorology as a whole.

"Look, I’m not saying I could do it better than them," Belichick said. "I’m just saying they’re wrong a lot. That’s a fact. They’re wrong a lot. We all make mistakes. I’m not being critical of them, I’m just saying I don’t think you can go based on that."

Belichick's stance on the local weatherman isn't out of malice -- it's out of experience. This is Belichick's 15th season in Foxborough as a head coach (not to mention his time as an assistant under Bill Parcells). He's familiar with the famous finicky weather in the region.

It's like the old Mark Twain quote: "If you don't like the weather in New England now, just wait a few minutes."

"My experience of going with the forecast in this area two days before the game, I mean I’d bet a lot that they’re wrong, just based on history because they’re almost always wrong. An hour before the game, maybe. You might have something to work with there. I think [if] you start game planning for what the weather is going to be and you game plan wrong, you’ve wasted a lot of time."

Belichick backed up his stance by recalling last week's forecast, which called for rain. By the time the Patriots had finished their blowout win over the Chicago Bears, though, nary a drop had fallen.

"When you play in New England, you have to be ready for everything. I’d say based on the forecasts we’ve gotten so far this year, none of them have been even very close to what game conditions were. There was 100 percent chance of rain last week and the only water I saw was on the Gatorade table."

For Belichick, it seems, the only really reliable forecast is when you take the field. So, it's more a less a Karen Smith from "Mean Girls" forecast:

"When you walk out on the field. I mean, that’s really when you know what it is. I mean, the rest of it is really just a bunch of hot air. We played down in Miami two years ago and there was a zero percent chance of rain – zero – and it rained. I’m just telling you. If I did my job the way they do theirs, I’d be here about a week."

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