Science. A supermassive black hole lurks at the edge of the universe

Madrid, 24 (European press)

The discovery of the galaxy and the black hole at its center provides new clues about the formation of the first supermassive black holes. The new work has been published in the Monthly Notices of the Royal Astronomical Society.

Using observations made with the Atacama Large Millimeter Array (ALMA), a radio observatory located in Chile, the team determined that the galaxy, called COS-87259, containing this new supermassive black hole is extremely intense, star-forming at a rate 1,000 times greater than our own. The Milky Way contains more than a billion solar masses of interstellar dust. The galaxy shines as much from this intense rush of star formation as from the growing supermassive black hole at its centre.

A black hole is a new type of primordial black hole, heavily shrouded in cosmic “dust”, and emitting almost all of its light in the mid-infrared of the electromagnetic spectrum. Researchers have also discovered that this growing supermassive black hole (often called the active galactic nucleus) generates a powerful jet of material that travels at near the speed of light through its host galaxy.

Today, at the center of nearly every galaxy are black holes millions to billions of times the mass of our Sun. How these supermassive black holes form is still a mystery to scientists, especially since many of these objects were discovered when the universe was very young. Because the light from these sources takes so long to reach us, we see them as they were there in the past; In this case, only 750 million years after the Big Bang, which is roughly 5% of the current age of the universe.

The most surprising thing about this new object is that it was discovered in a relatively small region of the sky (less than 10 times the size of the full moon), which indicates that there may be thousands of similar sources in the early universe. This is a completely unexpected finding from the previous data.

The only other class of supermassive black holes that we knew of in the early universe were quasars, which are active black holes that are relatively poorly masked by cosmic dust. These quasars are extremely rare at distances similar to those of COS-87259, with only a few dozen across the entire sky. The sudden discovery of COS-87259 and its black hole raises many questions about the abundance of very early supermassive black holes, as well as the types of galaxies in which they usually form.

“These results indicate that supermassive black holes were often heavily obscured by dust, possibly as a result of intense star formation activity in their host galaxies,” Ryan Endsley, lead author of the paper and now a postdoctoral fellow at the University of Texas at Austin, said in a statement. This is something others had predicted several years ago, and it’s really good to see the first direct observational evidence supporting this scenario.”

Similar objects have been found in the more localized current universe, such as Arp 299 shown here. In this system, two galaxies collide with each other resulting in an intense starburst, as well as a powerful dimming of the growing supermassive black hole in one of the two galaxies.

Endsley adds: “While no one expected to find this type of object in the early universe, its discovery is a step towards a much better understanding of how black holes with a mass of one billion solar masses formed so early in the life of the universe, as well as how the most massive galaxies evolved.” for the first time. “