New observations from the James Webb Space Telescope have revealed fresh details about one of the most luminous known objects in the universe: the dust-shrouded quasar W2246−0526, seen just 1.2 billion years after the Big Bang. The paper outlining the results was published in the Monthly Notices of the Royal Astronomical Society on May 14.
Hot DOGs
W2246−0526 is a hot dust-obscured galaxy, also known as Hot DOG, that is mainly powered by an actively feeding supermassive black hole at its center. Hot DOGs are extremely luminous, with their luminosities at infrared wavelengths exceeding 1014 times that of the luminosity of the sun, making astronomers wonder what causes them to reach such extreme brightness.
At z = 4.6, W2246−0526 is the most distant and luminous of its kind discovered so far. Previous studies have shown that it is dominated by hot dust whose temperatures reach 450 Kelvin or almost 180 degrees Celsius. The high temperature of this range suggests the domination of an active galactic nucleus (AGN).
In the new study led by Charalambia Varnava of the European University Cyprus, researchers conducted a multiwavelength analysis of the galaxy’s spectral energy distribution (SED), including observations from the James Webb Space Telescope. Their goal was to find out what physical components best explain the unique pattern of light coming from this object.
They explored the properties of this Hot DOG with different models of the dusty ring surrounding the black hole—known as the AGN torus—which were tested in combination with models for star formation and the host galaxy itself.
Dusty breakthrough
The team’s analysis revealed that a standard explanation incorporating the black hole’s torus, a star-forming region, and the surrounding galaxy failed to explain the mid-infrared light coming from W2246−0526. However, when they compared the same models, but with an added component of polar dust—clouds of dust sitting in the polar regions: above and below the black hole, rather than just around its equator—with the observations, there was a breakthrough.
The scenario, in which the torus is viewed edge-on with the dust clouds also occupying the polar regions, was found to be the most plausible explanation for the observed light. The polar dust component absorbs high-energy radiation and re-emits it at lower energies, acting as an additional source of infrared emission.
“For all models, the inclusion of polar dust statistically significantly improves their fit to the data of W2246−0526,” the team writes in the paper. “We argue that the observed infrared SED of W2246−0526 can be most plausibly explained by re-radiation by optically thick dust clouds in the polar regions of the torus, as well as an optically thick torus viewed almost edge-on.”
The researchers are careful to describe their polar dust detection as “indirect evidence.” They are inferring its presence from how well the models fit the data, not from a direct detection or image of the dust itself.
Oversized beast?
The study also provides some updated measurements about the system’s properties. W2246−0526 hosts a black hole with a mass of up to 23 billion suns while forming stars at rates potentially thousands of times higher than the Milky Way.
This enormous black hole accounts for roughly 72% to 81% of the galaxy’s total energy output. Notably, the starburst episode driving this intense star formation appears to be only tens of millions of years old.
The new estimate of the black hole mass and the luminosity is approximately two to three times higher than previous estimates. At this newly estimated mass, W2246−0526 appears to have a black hole slightly more massive than what would typically be expected for a galaxy of its size.
The disagreement with the previous estimate could also suggest that the black hole is feeding at a rate several times above the theoretical maximum in a phenomenon known as super-Eddington accretion.
Finally, if these results are confirmed, the methodology presented in this study could serve as a powerful technique to detect polar dust in distant, heavily obscured black holes across the early universe. It could also help uncover many more extreme hidden Hot DOGs and other AGNs like W2246−0526 that current imaging and spectroscopy may miss.
Written for you by our author Shreejaya Karantha, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.
Publication details
Charalambia Varnava et al, JWST observations and a model for the extremely luminous obscured quasar W2246−0526 at z = 4.6, Monthly Notices of the Royal Astronomical Society (2026). DOI: 10.1093/mnras/stag795
© 2026 Science X Network
Citation:
Universe’s most distant ‘Hot DOG’ yet may owe extreme infrared glow to polar dust, Webb reveals (2026, May 25)
retrieved 25 May 2026
from https://phys.org/news/2026-05-universe-distant-hot-dog-owe.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.