James Webb telescope zooms in on a black hole that could reveal the truth about ‘little red dots’
A unique black hole spewing X-rays could help confirm the enigmatic identity of “little red dots“, a curious class of objects observed mainly in the very early universe, about 12 billion light years away.
Astronomers have been seeking to classify small red dots (LRDs) since James Webb Space Telescope (JWST) first spotted them shortly after its science operations began in 2022.
Now, in an article published March 16 in Letters from the astrophysical journalastronomers have described an object that could shed light on the murky nature of LRDs.
Formerly known as 3DHST-AEGIS-12014 and colloquially referred to as an X-ray dot (XRD), this object remained hidden in a study conducted by NASA’s Chandra X-ray Observatory more than a decade ago. Its importance was only recently revealed, after JWST observed the same cosmic field.
“It’s always wonderful to see archival data help solve mysteries that were completely unknown when the data was first collected.” Antoine Tayloran astrophysicist at the University of Texas at Austin who was not involved in the study, told Live Science via email. “This is a great example of legacy science programs continuing to provide scientific value from their initial release and into the future.”
A single black hole could solve two cosmic mysteries
The XRD discovered by Chandra resembles an LRD, with a few differences. The most important thing is that it is a light source of X-ray light.
Normally, LRDs do not appear to emit X-rays. This anomaly has deepened the mystery of their identity, as active black holes typically emit X-rays from their chaotic crownswhere the penetrating material reaches near-light speeds and intense temperatures.
An illustration depicting a close-up view of the “x-ray point”.
(Image credit: NASA/CXC/SAO/M. Weiss; adapted by K. Arcand & J. Major)
“If the little red dots are fast-growing supermassive black holes, why don’t they emit X-rays like other black holes of this type?” co-author Anna de Graaffastrophysicist at the Harvard & Smithsonian Center for Astrophysics, said in a statement.
As suggested in this study and previous research, X-rays may be blocked by thick cocoons of gas surrounding the LRDs.
The XRD offers evidence of this process. As the black hole at its heart fills with surrounding gas, it releases holes in its cocoon. This forms sight lines inside the object and allows X-rays to escape, while preserving its overall reddish appearance – imagine a cosmic jack-o-lantern with its eerie interior light bleeding into the darkness.
“This single radiological object could be, to use a phrase, what allows us to connect all the dots,” said the lead author. Raphael Hvidingan astronomer from the Max Planck Institute for Astronomy in Germany, said in the statement.
The little red dots, as they appeared more than 12 billion years ago, were discovered through studies carried out in the early universe.
(Image credit: NASA, ESA, CSA, STScI, Dale Kocevski (Colby College))
Unveiling an enigma of the first universe
Overall, the XRD could help reinforce the idea that LRDs are young black holes in the midst of a transition phase, during which they are enveloped in a dense cloud of gas. This gaseous envelope is similar in composition to certain stellar atmospheres, which gives LRDs an impressive name: “black hole stars“.
As a result, if LRDs represent a phase of rapid gas accumulation by young black holes, this period of rapid consumption may help explain how first supermassive black holes (SMBH) grew so quickly, accumulating several million or billion solar masses when the universe was only about 10% of its current age.
It is essential to study the evolution of these objects in more recent times. “LRD type objects have indeed been found in the modern universe but it is clear that LRD analogues are extremely rare,” Hviding told Live Science by email. “Why? The short answer is that we don’t know. » One possibility is that the giant reservoirs of gas become thinner as the universe evolves, he said.
New generation observatories like the Nancy Grace Roman Space Telescope will scan the skies for rare and modern LRDs in the evolved universe. “They can’t go as deep or as precisely as Webb,” Hviding added, “but as they study large areas of the sky, finding rare analogues becomes viable.”
In the meantime, the XRD warrants further observations. Maybe it’s not an aged LRD after all, but a more common SMBH veiled in exotic dust never before seen. Either way, astronomers appear to have made a peculiar discovery that could elucidate a chain of cosmic mysteries in the evolution of the universe.
Hviding, RE, De Graaff, A. and H. 翰. L., Goulding, AD, and Y. 逸. M., Greene, JE, Boogaard, LA, Bunker, AJ, Cleri, NJ, Franx, M., Hirschmann, M., Leja, J., Matthee, J., Naidu, RP, Setton, DJ, Übler, H., Venturi, G., and 王 B. 冰. Yes. W. (2026). The X-Ray dot: exotic dust or small late red dot? Letters from the astrophysical journal, 1000(1), L18. https://doi.org/10.3847/2041-8213/ae4c88
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