New James Webb Space Telescope (JWST) observations are shedding light on W2246-0526, the most luminous and most distant "Hot DOG" galaxy ever found. The study suggests its extreme infrared brightness may come not just from its central black hole, but from clouds of hot dust above and below the galaxy's core. The findings were published in the Monthly Notices of the Royal Astronomical Society on May 14.
W2246-0526 sits at redshift 4.6, meaning we see it as it was just 1.2 billion years after the Big Bang. Classified as a Hot, Dust-Obscured Galaxy, or "Hot DOG", it's powered by a rapidly feeding supermassive black hole buried in thick dust.
The dust absorbs intense radiation from the black hole and re-emits it as infrared light, making Hot DOGs some of the brightest objects in the universe, outshining the Milky Way by up to 1,000 times.
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Led by Charalambia Varnava of European University Cyprus, the team modelled W2246-0526's spectral energy distribution using Webb data plus observations from other telescopes.
Their goal was to figure out what mix of dust, stars, and black hole activity best explains the galaxy's unique infrared signature.
The results, published May 14 in Monthly Notices of the Royal Astronomical Society, point to more than the usual dusty ring around the black hole, known as the AGN torus.
The models work best when they include additional "polar dust": clouds of heated dust extending along the black hole's rotation axis, above and below the torus.
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This polar dust reaches temperatures around 450 K, or nearly 180 degrees C, consistent with material being blasted outward by the black hole's energy output.
"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."
