Artist impression of W2246-0526, a galaxy glowing in infrared light as intensely as 350 trillion suns. It is so violently turbulent that it may eventually jettison its entire supply of star-forming gas, according to new observations with ALMA. Credit: NRAO/AUI/NSF; Dana Berry / SkyWorks; ALMA (ESO/NAOJ/NRAO)
Obscured quasar 12.4 billion light-years away – is so violently turbulent that it may eventually jettison its entire supply of star-forming gas, according to new observations with ALMA. A team used ALMA to trace, for the first time, the actual motion of the galaxy’s interstellar medium – the gas and dust between the stars. What they found, according to Tanio DÃaz-Santos of the Universidad Diego Portales in Santiago, Chile, is a galaxy “so chaotic that it is ripping itself apart.”
Previous studies with NASA’s Wide-field Infrared Survey Explorer (WISE) spacecraft revealed that the galaxy, dubbed W2246-0526, is glowing in infrared light as intensely as ~350 trillion suns. Evidence strongly suggests that this galaxy is an obscured quasar, a very distant galaxy with a voraciously feeding supermassive black hole at its center that is completely obscured behind a thick blanket of dust.
This galaxy’s startling brightness is powered by a tiny, yet incredibly energetic disk of gas that is being superheated as it spirals in on the supermassive black hole. The light from this blazingly bright accretion disk is then absorbed by the surrounding dust, which re-emits the energy as infrared light. This has a direct and violent impact on the entire galaxy, producing extreme turbulence throughout the interstellar medium. If these conditions continue the galaxy’s intense infrared radiation will boil away all of its interstellar gas.
This galaxy belongs to a very unusual type of quasar known as Hot, Dust-Obscured Galaxies or Hot DOGs. These objects are very rare; only 1 out of every 3,000 quasars observed by WISE belongs to this class.
ALMA mapped the motion of ionized carbon atoms throughout the entire galaxy. These atoms, which are tracers for interstellar gas, naturally emit infrared light, which becomes shifted to millimeter wavelengths as it travels the vast cosmic distances to Earth due to the expansion of the Universe. The data reveal that this interstellar material is careening anywhere from 500 to 600 km/s throughout the entire galaxy.
The astronomers believe this turbulence is primarily due to the fact that the region around the black hole is at least 100 times more luminous than the rest of the galaxy combined; in other quasars, the proportion is much more modest. This intense yet localized radiation exerts tremendous pressure on the entire galaxy, to potentially devastating effect. “We suspected that this galaxy was in a transformative stage of its life because of the enormous amount of infrared energy discovered with WISE,” said Peter Eisenhardt, JPL. “Now ALMA has shown us that the raging furnace in this galaxy is making the pot boil over.”
Current models of galactic dynamics combined with ALMA data indicate that this galaxy is unstable and its interstellar gas is being blown away in all directions. This suggests that the galaxy’s Hot DOG days are numbered as it matures into a more traditional unobscured quasar.
http://www.eurekalert.org/pub_releases/2016-01/nrao-etr011416.php
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