Twelve billion years ago, when the whole space it was just a new universe, a new galaxy reminiscent of the Milky Way was lighting up life deep in the cosmos. Astronomers have often thought of this early universe as a chaotic, extreme environment where galaxies are unstable and violent. New research suggests that assumptions may be inaccurate, providing a new insight into how galaxies form.
In a new study, published in the journal Nature on Wednesday, observations made by the Atillama Large Millimeter / submillimeter Array (ALMA) of Chile SPT – S J041839–4751.9, or SPT0418-47 for February, show that the baby galaxy has features similar to those of our more mature Milky Way. It took light from the galaxy 12 billion years to reach us. This means that astronomers are looking in time at a galaxy that formed less than 1.5 billion years after the birth of the universe.
Previous modeling and observations have led astronomers to theorize that the period after the birth of the universe was turbulent. Early galaxies were probably colliding with each other and melting to form large, disordered masses of stars. They should not be placed on regular, flat disks. But SPT0418-47 does, and that’s a surprise that awakens some of our beliefs about early cosmic activity in the universe.
“This result represents a breakthrough in the field of galaxy formation, showing that the structures we observe in nearby spiral galaxies and in our Milky Way were already in place 12 billion years ago,” said Francesca Rizzo, an astronomer at Ph.D. D. student at the Max Planck Institute of Germany for Astrophysics and the first author of the study, said in a statement.
Because SPT0418-47 is so far away, it is hard to find in the sky because its light is so dim. To find and characterize SPT0418-47, the research team utilized a phenomenon known as “gravitational lensing.” Light from distant galaxies does not travel in a straight line on Earth – it is affected by the effects of gravity on its way here. Nearby galaxies distort and reshape light from more distant galaxies as they travel through our telescopes.
But lensing can help with detection. Using the ALMA technique and telescope, the researchers were able to magnify light from SPT0418-47 and increase the resolution to observe the features of the new galaxy. The lensing effect means the images taken by ALMA show SPT0418-47 as an aggressive, fiery Sauron-type ring, a perfect circle of light containing hundreds of thousands of stars.
Using computer modeling techniques, the research team took the circular gravitational lens images of the SPT0418-47 and reconstructed what the galaxy would look like if our telescopes were powerful enough to see it for themselves (as the video below shows) . Modeling reshaped the galaxy in a surprising way.
“When I first saw the reconstructed image of SPT0418-47 I could not believe it,” Rizzo said. “A treasure chest was opening.”
The reconstruction showed that the SPT0418-47 does not have the large, helical wings we are used to seeing in the Milky Way, but it does have a disk and a giant bulge at its center, reminiscent of our home galaxy. The Southern European Observatory suggests it is a view of the Milky Way.
“It’s less of a picture and more of a mini-me,” said Sarah Martell, an astrophysicist at the University of New South Wales who was not involved in the study. “It’s only 25% of the Milky Way mass and half the size.”
But what the stature lacks, it constitutes the power of the star. The rate of galaxy star formation is equal to the mass of our 350 sun, which Martell calls “large.” By comparison, she observes, the Milky Way star formation rate is only 1.6 solar masses per year. Simona Vegetti notes that the level of star formation is “quite annoying” because it means the galaxy as a place of very energetic processes. Apparently, this would lead to more disorder, but SPT0418-47 remains enjoyable and calm even with all that activity.
The new galaxy will not evolve into a spiral Milky Way galaxy like the ones we are familiar with today. Instead, researchers believe it will become an elliptical galaxy like Messier 87,. Such a fate will not happen for millions of years. However, when the extremely large Southern European Observatory telescope hits the internet in 2025, astronomers are likely to find more of these commissioned galaxies, allowing them to discover how they could form and evolve in the early universe. .