I guess this week’s theme is bright interstellar objects. First, it was the brightest supernova ever discovered. Now, scientists are taking a closer look at the most luminous galaxy in the Universe.
W2246-0526 lies 12.4 billion light-years away. Researchers say it is so turbulent that it could eventually throw away all of the galaxy’s star-forming gas. Well actually, it probably already did. We are looking at light that took 12.4 billion light-years to reach us.
According to the National Radio Astronomy Observatory, astronomers compare what’s going on with W2246-0526 to a pot of boiling water. To better understand what’s going on, let’s take a look at what makes this galaxy so bright. NASA’s Wide-field Infrared Survey Explorer (WISE) spacecraft showed W2246-0526 glowing in infrared light as brightly as 350 trillion suns. It all starts with a tiny, but incredibly active disk of gas.
As the disk of gas spirals towards the supermassive black hole, it is superheated. The blinding light produced from this process is absorbed by the surrounding dust and reemitted as infrared radiation.
“These properties make this object a beast in the infrared,” said Roberto Assef, an astronomer and leader of the ALMA observing team. “The powerful infrared energy emitted by the dust then has a direct and violent impact on the entire galaxy, producing extreme turbulence throughout the interstellar medium.”
Observations of W2246-0526 point to the galaxy being an obscured quasar. The supermassive black hole at the galaxy’s center is covered by dense layers of dust. And astronomers have the perfect acronym for it. Hot DOGs, or Hot, Dust-Obscured Galaxies. Yep, you know the person who came up with that one gave themselves a pat on the back.
What ALMA found
ALMA. Credit: ESO
Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers mapped how ionized carbon atoms where moving through the entire galaxy.
“Large amounts of ionized carbon were found in an extremely turbulent dynamic state throughout the galaxy,” said Tanio Díaz-Santos of the Universidad Diego Portales in Santiago, Chile.
How turbulent are we talking? These atoms are bumping around at 500 to 600 kilometers per second across the whole galaxy, and it’s all because of what’s happening right around the black hole. That disk of gas I mentioned above? It’s at least 100 times brighter than the rest of the galaxy combined.
Galactic dynamics models, combined with the ALMA data, show the galaxy’s gas being thrown out in all directions.
Manuel Aravena (also from the Universidad Diego Portales) has a grim prognosis for W2246-0526. “If this pattern continues, it is possible that in the future W2246 ends up shedding a large part of the gas and dust it contains,” says Aravena.