Astronomers have decoded the inner workings of a “Little Red Dot” for the first time. This point of light from the early cosmos hides a supermassive black hole of around 50 million solar masses – it is the first mass determination of such an object so shortly after the Big Bang, as the team reports in “Nature”. The black hole is also almost “naked” because there are surprisingly few stars in its surroundings. This calls into question classic scenarios for the evolution of early supermassive black holes.
The “Little Red Dots,” which only existed in the early cosmos, are puzzling astronomers. Because these reddish points of light visible in images from the James Webb Space Telescope are too bright and compact for a dust-shrouded early galaxy, but too large and massive for globular clusters and other stellar objects.
Some astronomers suspect they could be “black hole stars” – massive black holes surrounded by dense hydrogen gas. Others think the Little Red Dots are active galactic nuclei – massive black holes at the center of gas-rich, star-poor galaxies. However, most light points lack the typical X-ray radiation. Astronomers have recently detected X-rays in only one of the “Little Red Dots”, which strengthens the assumption that an active black hole is the cause.
Enlarged by gravitational lensing
Now, more detailed insights into one of the Little Red Dots provide confirmation. The focus was on the object Abell 2744-QSO1, a point of light discovered in 2023 at a distance of around 13 billion light-years. Because this object’s radiation is amplified and magnified by a cluster of galaxies in the foreground, its features are easier to see than most other Little Red Dots. Initial spectral analyzes suggested that an active black hole could be hidden behind this point of light.
To find out more, Ignas Juodžbalis from the University of Cambridge and his team have now analyzed new data from the near-infrared spectrograph (NIRSpec) on the James Webb Telescope. They used the spectral signature of excited hydrogen to measure the distribution and velocity of gases in this object. From this they determined the size and mass of the black hole presumably hidden in the center.
Mass concentrated in one point
The result: The spectral features confirm that the object QSO1 is extremely compact. Although it weighs millions of solar masses, its radius is only around 1,300 light years. “This object is ten times denser than the densest star clusters in the local or early universe,” report Juodžbalis and his team. Almost the entire mass of this Little Red Dot appears to be concentrated in one point.
This was also confirmed by the gases rotating rapidly around this center of mass. “The data reveals a rotation curve that does not fit the core of a star cluster,” the astronomers write. “Instead, this movement can be explained by rotation around a point mass of around 50 million solar masses.” But that means: There must be a massive black hole at the core of this Little Red Dot.
“This is a phenomenal result,” says co-author Roberto Maiolino from the University of Cambridge. “It is the first direct mass determination of a black hole from less than a billion years after the Big Bang. At the same time, it confirms that there are massive black holes in the Little Red Dots.
The “naked” black hole ever discovered
But there is another special feature: Unlike active galactic nuclei and supermassive black holes in today’s cosmos, QSO1 is surrounded by unusually few stars, as the astronomers found. “We arrive at a dynamic upper limit for the stellar mass of less than 20 million solar masses,” report Juodžbalis and his team. This means that this early black hole is more than twice as massive as the rudimentary galaxy surrounding it.
“To our knowledge, this makes QSO1 the ‘naked’ black hole ever found,” the astronomers explain. In their view, this suggests that QSO1’s massive black hole did not grow along with its host galaxy. Instead, it must have existed before the galaxy. This is also indicated by the chemically very pristine environment of this black hole, as it is surrounded by almost pure hydrogen and helium.
“This demonstrates a possible primacy of black holes – black holes that form and grow earlier than their host galaxies,” the team writes.
Evidence for “heavy seeds” of early black holes
However, how the black hole QSO1 was able to grow so large and so quickly without a galaxy is still unclear. “The only scenarios that could explain such a system would be ‘heavy seeds’ such as black holes formed by the direct collapse of gas clouds or primordial black holes that formed in the first second after the Big Bang,” explain the astronomers. Maiolino adds: “This is a paradigm shift, a total transformation of the classic scenarios for the formation and growth of black holes.”
Source: Ignas Juodžbalis (University of Cambridge) et al., Nature, 2026; doi: 10.1038/s41586-026-10579-4