Skip to main content

Pairs of supermassive black holes spotted in colliding galaxies

We know that our universe is full of black holes, existing everywhere from between ancient strange clusters of stars to the massive black hole at the center of the Milky Way. Now astronomers from the Swiss Federal Institute of Technology (ETH) in Zurich have discovered several pairs of supermassive black holes located at the center of galaxies which are colliding together.

The scientists were examining what happens when two galaxies merge together into one larger galaxy. The process of collision generates huge amounts of gas and dust around the cores of the galaxies, which makes it difficult to see what is happening within. But the scientists were able to identify two supermassive black holes at the center of the two original galaxies which are drawing closer together and which will eventually coalesce into one enormous black hole.

The team used images from the W.M. Keck Observatory in Hawaii and NASA’s Hubble Space Telescope to survey nearby galaxies and to find pairs of galaxies which were merging. In total, they looked at 385 galaxies from the archive of Hubble images and 96 galaxies from the Keck telescope. Using Hubble images, they were able to identify galaxy NGC 6240, whose two cores have nearly melded and which could be seen through infrared light which pierces the dust and gas around the central core. Four other merging galaxies were also discovered from the Keck Observatory data, which used near-infrared light and adaptive optics to identify merging galaxies.

Overall, the findings suggest that more than 17% of the galaxies that they studied had a pair of black holes at their center which were spiraling closer and closer together. Eventually, all of these pairs of black holes will come together to form an even larger black hole, which should happen in the next 10 million years. That might sound like a long time, but in cosmic terms it’s very soon.

“This is the first large systematic survey of 500 galaxies that really isolated these hidden late-stage black hole mergers that are heavily obscured and highly luminous,” lead researcher Dr. Michael Koss told Science News. “It’s the first time this population has really been discovered. We found a surprising number of supermassive black holes growing larger and faster in the final stages of galaxy mergers.”

The findings are published in Nature.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Hubble captures a messy irregular galaxy which hosted a supernova
The irregular spiral galaxy NGC 5486 hangs against a background of dim, distant galaxies in this image from the NASA/ESA Hubble Space Telescope. The tenuous disk of the galaxy is threaded through with pink wisps of star formation, which stand out from the diffuse glow of the galaxy’s bright core.

This week's image from the Hubble Space Telescope shows a dramatic spiral galaxy called NGC 5486, which is shot through with wisps of pink showing regions where new stars are being born.

Located 110 million light-years away in the famous constellation of Ursa Major, this galaxy is a type called an irregular spiral galaxy because its arms are wandering and indistinct. If you compare the image of this galaxy to one of a quintessential spiral galaxy like NGC 2336, you'll see that a non-irregular spiral galaxy has clearly defined arms that reach out from its center and are symmetrical.

Read more
Hubble captures a cosmic sea monster with this image of a jellyfish galaxy
A jellyfish galaxy with trailing tentacles of stars hangs in inky blackness in this image from the NASA/ESA Hubble Space Telescope. As Jellyfish galaxies move through intergalactic space they are slowly stripped of gas, which trails behind the galaxy in tendrils illuminated by clumps of star formation. These blue tendrils are visible drifting below the core of this galaxy, and give it its jellyfish-like appearance. This particular jellyfish galaxy — known as JO201 — lies in the constellation Cetus, which is named after a sea monster from ancient Greek mythology. This sea-monster-themed constellation adds to the nautical theme of this image.

This week's image from the Hubble Space Telescope shows a special and delightful cosmic object: a jellyfish galaxy. These galaxies are named for their larger main body with tendrils that float along after them, like the sea creatures.

This particular jellyfish galaxy is called JO201, and is located in the constellation of Cetus. Appropriately for the sea theme, Cetus is a constellation named after a Greek mythological sea monster that sometimes had the body of a whale or serpent along with the head of a boar. In the image, you can see the main body of the galaxy in the center, with the trailing tendrils spreading down toward the bottom of the frame.

Read more
James Webb spots ‘universe-breaking’ massive early galaxies
Images of six candidate massive galaxies, seen 500-700 million years after the Big Bang. One of the sources (bottom left) could contain as many stars as our present-day Milky Way, according to researchers, but it is 30 times more compact.

The James Webb Space Telescope continues to throw up surprises, and recently it has been used to spot some very old galaxies which have astonished astronomers. The galaxy candidates are far more massive than anyone expected would be possible, challenging assumptions about the early universe.

An international team of astronomers spotted six potential galaxies in a region of space close to the Big Dipper constellation from just 500 to 700 million years after the Big Bang, when the universe was still in its infancy. “These objects are way more massive​ than anyone expected,” said one of the researchers, Joel Leja of Penn State. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”

Read more