James Webb Space Telescope (JWST) observations of what astronomers call “little red dots” have intrigued researchers since their discovery in 2022.
Now, new data on the spectra of one of these dots, made possible with imagery obtained by Webb, may hold the answers researchers have long sought.
In a recent paper published in The Astrophysical Journal, a team of astronomers led by the University of Texas at Austin’s Vasily Kokorev revealed their intriguing observations of the little red dot GLIMPSE-17775 using the JWST.
Data collected by the JWST support the BH* scenario, the hypothesis that little red dots are supermassive black holes surrounded by a cloud of partially ionized gas.
JWST and the Little Red Dot
The recent JWST observation of GLIMPSE-17775 is the deepest spectral view of a little red dot ever captured, spanning 40 spectral lines and offering a powerful opportunity to compare the data with various theories about the object’s origins. Born only about 1.8 billion years after the Big Bang, or about 12 billion years ago, the object hails from the universe’s early days.
As with many of science’s most interesting discoveries, this observation was a fortunate accident, captured as the JWST was observing the Abell S1063 galaxy cluster, located in front of GLIMPSE-17775 from our point of view.
Gravitational lensing magnifies GIMPSE-17775, allowing JWST a better look at the object despite its extreme distance, and making the 30-spectrum JWST captured equivalent to hours of observations.
“When we saw the spectrum for the first time, it was like having all the pieces of a puzzle scattered on the floor,” said Kokorev. “We picked up each piece of the puzzle, measured the lines, and started combining the different pieces into a mosaic. Maybe a few pieces looked like nothing at first, but then a couple of them came together, and we realized that there was something there.”
Explaining Little Red Dots
First appearing at around 600 million years after the Big Bang, the mysterious little red dots have puzzled scientists since they first came to light. The black hole scenario is just one of several that researchers have proposed as a possible explanation, although it is currently gaining the most support as more data comes in.
“I think part of the scientific community is converging on a singular picture — that little red dots can be explained by black hole star models. But none of the previous little red dots have all of the pieces of evidence in the same place,” Kokorev said. “With GLIMPSE-17775, we can test these models because of how deep and amazing this source’s spectrum is.”
The researchers interpret the data as showing a rapidly accreting black hole covered by a dense gas cocoon that reprocesses the black hole’s light into the spectrum observed by JWST.
Comparing the spectra to various models revealed some intriguing evidence for the BH* scenario. The helium, oxygen, and hydrogen lines don’t fit a simple rotating gas cloud model, but do correspond to an electron scattering, a broadening effect associated with a dense, layered gas cocoon.
Other lines, such as the 16 iron lines, suggest a powerful energy source, which could indicate a rapidly accreting black hole. Additionally, helium absorption and fluorescence are seen in the spectrum, signs that a powerful energy source is enveloped in a dense medium.
What JWST Didn’t See
Beyond this incredibly deep spectrum, other little red dot observations have been faint in X-rays, a form of emission that the gas cocoon, in the BH* scenario, is likely to absorb.
One strange quirk of GLIMPSE-17775 is that the spectrum was missing the portion that would indicate the little red dots’ signature dip in light emission, known as a Balmer break. However, supplementary data collected by the Hubble Space Telescope resolved this issue, identifying that interference from a giant host galaxy is the root cause.
“Everything fits, nothing is broken, and I think that makes the puzzle that is our universe even better,” Kokorev concluded. “Looking ahead, I’m eager to dive deeper and learn about what is powering the central engines of little red dots. While we think it’s a black hole, there are some other interesting theories being proposed, which is exciting. Maybe in a year or two, we’ll have the final answer to what powers these sources.”
The paper, “The Deepest GLIMPSE of a Dense Gas Cocoon Enshrouding a Little Red Dot,” appeared in The Astrophysical Journal on June 10, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.