Astronomers have discovered the earliest known flickering quasar, a powerful object powered by a supermassive black hole.
The discovery is helping scientists learn more about how giant black holes formed so quickly in the early universe.
A supermassive black hole sits at the center of almost every galaxy, including our own Milky Way.
When these black holes actively pull in gas and dust from their surroundings, the material forms a spinning disk around them.
As the material heats up, it releases enormous amounts of energy, creating some of the brightest objects in the universe, known as quasars.
Now, researchers from MIT and other institutions have found a quasar that existed just 850 million years after the Big Bang. This makes it the earliest flickering quasar ever detected.
Scientists have discovered many quasars from the universe’s early days before, but this is the first one whose brightness has been seen changing, or “flickering,” over time.
The flickering is important because it provides clues about what is happening close to the black hole. Just as a candle flame flickers when air currents change, a quasar’s light can vary when the flow of gas into the black hole changes.
By studying these changes, researchers were able to learn about the shape of the quasar’s accretion disk—the swirling disk of gas and dust feeding the black hole.
What surprised them was that the disk appeared very thin and flat, much like the disks seen around mature black holes in the modern universe.
This finding raises new questions about how supermassive black holes grow.
Scientists have long believed that young black holes in the early universe should be messy and chaotic. Their surrounding disks were expected to be thick, puffy, and unstable because they were still growing rapidly.
Instead, this ancient black hole appears to have already settled into a stable structure, even though the universe was still very young.
The discovery adds to a long-standing mystery. Astronomers are still trying to understand how supermassive black holes became so enormous so quickly after the Big Bang. Some of these black holes already had masses billions of times greater than the sun when the universe was less than a billion years old.
To find the flickering quasar, the team analyzed 14 years of observations from NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). Because the quasar is so far away, its light has been stretched into infrared wavelengths as the universe expanded.
The researchers found that the quasar’s brightness changed randomly over the 14-year period. They estimate it shines with the power of about 12 trillion suns and varies in brightness by roughly 20%, equivalent to a change of about 2 trillion suns.
By examining the flickering at different wavelengths, the scientists could map the temperatures of material around the black hole and determine the structure of the accretion disk.
The results suggest that the same feeding processes seen around black holes today were already operating in the universe’s earliest quasars.
Researchers now hope to find even younger quasars to understand what happened before these black holes reached such a surprisingly mature state. Their future discoveries may finally reveal how the first supermassive black holes formed and grew so rapidly in the early universe.
Source: MIT.
