When the James Webb Space Telescope looks deep into the Universe, some of the objects it finds appear as small, red dots. Astronomers call them little red dots (LRDs), and they have become one of the telescope’s more intriguing discoveries.
For one, the exact mechanism by which the black hole and its dense envelope formed remains an open question.
That said, the study’s authors also stressed that their observation does not establish the idea conclusively.
In an independent commentary accompanying the paper, astronomers Dominik Schleicher of the Sapienza University of Rome and Rodrigo Herrera-Camus of the University of Concepción, Chile, wrote that the discovery could be important for scientists to understand other LRDs. For some years now, astronomers have not been able to make sense of how very massive black holes could exist when the universe was so young, less than a billion years old. If a black hole formed with the mass of a star, they wouldn’t be able to grow at the conventional rate to become supermassive so quickly. One possibility that the new study buttresses is that these black holes didn’t grow at the conventional rate.
The astronomers spotted the object in question in the study from when the universe was just around 660 million years old. Put another way, the light from this object has travelled for more than 13 billion years before reaching the earth, which the Webb telescope orbits. A study published in Nature on May 27 provided an important piece of the puzzle from a different direction. Astronomers studied a different LRD that existed when the universe was around 700 million years old. By measuring how gas was rotating around the object, they were able to estimate its mass: about 50 million-times that of the sun — which is high. The new study (from August 12) also offered a clue to how this could happen.
Astronomers had previously proposed that when a black hole is surrounded by a dense cloud of gas, it could grow faster than expected — and the hydrogen cocoon surrounding the newfound black hole presents just such a scenario.
The two galaxies are also expected to merge in roughly 100 million years. There is another intriguing detail. The researchers pointed out that if the black hole’s light and the neighbouring galaxy were eventually seen together, the combined object would look remarkably similar to a typical LRD. Schleicher and Herrera-Camus also noted that such gas-rich environments could help explain other peculiar properties of LRDs, including their surprisingly weak X-ray emissions. Future radio telescopes may also be able to probe the electrons moving through these environments and provide information that Webb is not designed to.
The object appears to be in a relatively small galaxy while a considerably more massive galaxy is located nearby, according to the study.
