Hubble Space Telescope captures a massive, fast-spinning dead disk galaxy. It stopped making stars only a few billion years after the Big Bang.
The study was published in the journal Nature. It was led by Sune Toft of the University of Copenhagen and other colleagues. This indicates that some dead galaxies develop into a three-dimensional elliptical galaxy, according to CNET.
Toft said that this new discovery may force them to rethink the whole cosmological context of how galaxies burn out early on and evolve into local-elliptical-shaped galaxies. He further said that perhaps they might have been blind to the fact that early dead galaxies could, in fact, be disks. This is because they have not been able to resolve them.
Phys.org reports that the scientists were surprised by the discovery. This is because elliptical galaxies contain older stars, while the spiral galaxies have younger blue stars. Some dead disk galaxies might have changed their structure and motions of their stars to form into an elliptical galaxy.
So, how did these young compact disks develop into the elliptical galaxies? Toft speculated that it might be through mergers. He further said that if these galaxies grow through merging with minor companions and these minor companions come in huge quantities and from all types of various angles onto the galaxy, this could randomize the orbits of stars in the galaxies. He also added that one could also think of major mergers and this could truly destroy the motion of the stars.
On the other hand, why the galaxy stopped developing stars is unclear. It might be the result of an active galactic nucleus, in which the energy is pouring from a supermassive black hole. Another reason could be the result of cold gas flowing onto the galaxy that is compressed and heated up. This inhibits it from cooling down into star-forming clouds in the core of the galaxy.
This galaxy is about three times the mass of the Milky Way, yet only half its size. It is also spinning twice as fast as the Milky Way. The scientists are hoping to use the James Webb Space Telescope to view the bigger sample of said galaxies.