Astronomers have detected a first-of-its kind compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the Big Bang. Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, the researchers said. The finding, published in the journal Nature, was possible with the capability of NASAs Hubble space telescope.

When Hubble photographed the galaxy, astronomers expected to see a chaotic ball of stars formed through galaxies merging together. Instead, they saw evidence that the stars were born in a pancake-shaped disk. This was the first direct observational evidence that at least some of the earliest so-called dead galaxies where star formation stopped somehow evolve from a Milky Way-shaped disk into the giant elliptical galaxies we see today.

This new insight may force us to rethink the whole cosmological context of how galaxies burn out early on and evolve into local elliptical-shaped galaxies, said study leader Sune Toft from University of Copenhagen, Denmark. Perhaps we have been blind to the fact that early dead galaxies could in fact be disks, simply because we havent been able to resolve them, Toft said. ALSO READ:NASAs Kepler space telescope discovers 10 near-Earth size, habitable planet candidates

The remote galaxy was three times as massive as the Milky Way but only half the size. Rotational velocity measurements made with the European Southern Observatorys Very Large Telescope (VLT) showed that the disk galaxy was spinning more than twice as fast as the Milky Way. Using archival data from the Cluster Lensing And Supernova survey with Hubble (CLASH), Toft and his team were able to determine the stellar mass, star-formation rate, and the ages of the stars. ALSO READ:NASAs Hubble telescope shows close-up image of Jupiter, Great Red Spot

Why this galaxy stopped forming stars was still unknown. It might be the result of an active galactic nucleus, where energy was gushing from a supermassive black hole. This energy inhibits star formation by heating the gas or expelling it from the galaxy. Or it might be the result of the cold gas streaming onto the galaxy being rapidly compressed and heated up, preventing it from cooling down into star-forming clouds in the galaxys centre. But how do these young, massive, compact disks evolve into the elliptical galaxies we see in the present-day universe? ALSO READ:Here are five interesting facts about NASAs Juno spacecraft orbiting Jupiter

Probably through mergers, Toft said.

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NASA's Hubble space telescope detects disk-shaped galaxy - BGR India