The galaxy W2246-0526 – the most luminous known galaxy in the Universe – is so turbulent that it is in the process of ejecting its entire supply of star-forming gas, according to a group of astronomers led by Dr. Tanio Diaz-Santos from the Universidad Diego Portales in Chile.
This is an artist’s impression of the hot, dust-obscured galaxy W2246-0526. Image credit: NRAO / AUI / NSF / Dana Berry / SkyWorks / ALMA / ESO / NAOJ.
“It is like a pot of boiling water being heated up by a nuclear reactor in the center,” explained Dr. Diaz-Santos, who is the first author of a study published last month in the journal Astrophysical Journal Letters (arXiv.org preprint).
W2246-0526 (WISE J224607.57-052635.0) is roughly 12.4 billion light-years away and was discovered in 2015 by astronomers using NASA’s Wide-field Infrared Survey Explorer (WISE).
It is an example of a rare class of galaxies called hot, dust-obscured galaxies (Hot DOGs), which are powerful objects with supermassive black holes in their centers.
This galaxy is also classified as an extremely luminous infrared galaxy (ELIRG). It is smaller than our own Milky Way Galaxy, yet puts out 10,000 times more energy (equal to more than 300 trillion Suns).
According to new observations with the Atacama Large Millimeter/submillimeter Array (ALMA), an astronomical interferometer of radio telescopes in the Atacama desert of northern Chile, W2246-0526 is so violently turbulent that it may eventually jettison its entire supply of star-forming gas.
“Large amounts of this interstellar material were found in an extremely turbulent and dynamic state, careening throughout the galaxy at around 2 million km per hour,” Dr. Diaz-Santos said.
Dr. Diaz-Santos and co-authors believe that this turbulent behavior could be linked to the galaxy’s extreme luminosity, which is powered by a tiny, yet incredibly energetic disk of gas that is being superheated as it spirals in on W2246-0526’s central black hole.
The light from this bright accretion disk is then absorbed by the surrounding dust, which re-emits the energy as infrared light.
“These properties make this object a beast in the infrared. 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,” said co-author Dr. Roberto Assef, also from the Universidad Diego Portales.
“We suspected that this galaxy was in a transformative stage of its life because of the enormous amount of infrared energy,” added co-author Dr. Peter Eisenhardt of NASA’s Jet Propulsion Laboratory.
“ALMA has now shown us that the raging furnace in this galaxy is making the pot boil over,” Dr. Assef said.
If these turbulent conditions continue, the infrared radiation would boil away all of W2246-0526’s interstellar gas.
“It is possible that W2246-0526 will eventually mature into a more traditional quasar,” said co-author Dr. Manuel Aravena, also from the Universidad Diego Portales.
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T. Diaz-Santos et al. 2016. The Strikingly Uniform, Highly Turbulent Interstellar Medium of the Most Luminous Galaxy in the Universe. ApJ 816, L6; doi: 10.3847/2041-8205/816/1/L6
