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The Universe's Brightest Galaxy Shines Like 300 Trillion Suns

NASA has discovered the most luminous galaxy yet, and they believe it has a massive black hole heart.
May 21, 2015, 7:20pm
An artist's illustration of the most luminous galaxy detected. Image: NASA

Sometimes when you gaze billions of years into our universe's past, you'll find something so stunning that even the cold, scientific terms to describe it sound poetic. Take the galaxy—the most luminous ever identified—that Jet Propulsion Lab scientists say shines "with the light of more than 300 trillion suns."

Astrophysicists have been combing through data from NASA's Wide-field Infrared Survey Explorer (WISE), an infrared space telescope launched in 2009, for evidence of a newly-discovered class of galaxies called extremely luminous infrared galaxies (ELIRGs). This particular galaxy—dubbed the decidedly unpoetic WISE J224607.57-052635.0—is the most luminous of the 20 they've found to date. The team's findings will be published in the next issue of The Astrophysical Journal.

But what makes this galaxy and other ELIRGs so bright? Researchers suspect massive black holes at their centers are to blame, according to a NASA release.

"Supermassive black holes draw gas and matter into a disk around them, heating the disk to roaring temperatures of millions of degrees and blasting out high-energy, visible, ultraviolet and X-ray light," NASA explains. "The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light."

The light from this ELIRG shines from 12.5 billion years ago, yet the black hole at its center was already billions of times more massive than our sun at the time that light was emitted. In their paper, the researchers propose three possible explanations for how the black holes at the center of ELIRGs grew so massive. It could be that the "seeds" for the black holes were big to begin with (bigger than we previously thought was possible) or it could be that the black holes are able to either break or bend the limit to how quickly we thought they could consume matter and grow.

"The massive black holes in ELIRGs could be gorging themselves on more matter for a longer period of time," Andrew Blain, an astronomer at the University of Leicester and co-author of the study, said in the release. "It's like winning a hot-dog-eating contest lasting hundreds of millions of years."

Just like hot-dog-eating contestants have to let out air in order to keep shoving more dogs in their mouth, growing black holes expel light as they consume matter. That light pushes away the matter, creating a limit to how quickly they can grow, according to NASA. In order to grow as massive as they did in the time they did, these ELIRGs might have had to either break or bend this limit, shaking up what we thought we knew about how black holes form. They might also just be spinning more slowly, allowing a black hole to consume more matter at a time.

To solve the puzzle, the next step will include measuring the exact mass of these giant black holes to determine just what we're dealing with. Luckily, the infrared imaging from the WISE makes this easier to do and will reveal untold secrets about how these galaxies, and their black hole centers, form.

In the meantime, we now all have a really great new pick up line to use: "Your eyes shine like an extremely luminous infrared galaxy."

If that doesn't set someone's heart aflutter, I don't know what will.