In the early Universe, approximately 10.8 billion years ago, astronomers have just spotted a galaxy with some severe “battle scars.”
It’s not a disc of stars or a blob at all, but a huge doughnut, with a giant hole right through its center. How did astronomers manage to spot such a cosmic feature? Also, why makes this galaxy so rare? Here is all you need to know.
Universe’s Ring of Fire is in the Spotlight Now
Astronomers succeeded in spotting a rare type of galaxy known as a ring galaxy. But the galaxy is rare even among that type. Its shape is made not by internal processes, but by a collision that torn apart its center as the other galaxy passed through. The galaxy is dubbed R5519, and it’s the first collisional ring galaxy ever discovered more than a few hundred light-years away. It is also the only found space object in the early Universe.
The outer edge of the galaxy is almost 42,400 light-years across, and its punched hole is approximately 17,612 light-years. There is no detectable trail of the star-packed bump that usually loads a galactic center. And some pieces of evidence hint at a harsh past.
There are ring galaxies that appear to have had relatively calm formations, produced by accretion of material from another nearby galaxy or an orbital resonance. R5519, however, shows a high rate of star formation in its ring – almost 80 solar masses’ worth of baby stars produced annually. Such a thing means that a gravitational disruption occurred – by, say, another galaxy striking through R5519, emitting density waves generating radially outwards.
“In the case of this ring galaxy, we are looking back into the early Universe by 11 billion years, into a time when thin disks were only just assembling,” explained Kenneth Freeman, an astronomer from the Australian National University.