The "natural lens" effect and the capabilities of the telescope made it possible to establish that the "close-packed" ancient galaxy MACS 2129-1 is half and three times more massive than the Milky Way, and stars have not been born in it for more than 10 billion years. MACS 2129-1 is a zombie galaxy.What?! Zombie Galaxy?
Yes, in astronomy there is such a thing as "zombie galaxies", and this class includes galaxies in which star formation has ceased for some reason.
MACS 2129-1 is one of the first discovered galaxies of such an unusual class, the discovery of which has become a "headache" for astronomers. Numerous observation sessions were unable to explain what caused the termination of star formation at such a young (at that time) age of the galaxy.MACS 2129-1 still has billions of stars, mostly red giants and red dwarfs that formed just a few billion years after the Big Bang. All these luminaries, like in any other galaxy, revolve around the center, but this happens two times faster than in the case of the stars of the Milky Way. This may indicate that there is a supermassive black hole lurking at the center of MACS 2129-1, which is possibly several times more massive than the Sagittarius A * black hole in the heart of our Galaxy.Why did MACS 2129-1 "burn out" so quickly?
Scientists are considering two theories that could explain the earlier extinction of star formation in the zombie galaxy:
The supermassive black hole hiding in the center has absorbed most of the gas, depriving the star formation process of the necessary fuel;
An abundance of cold gas got into the galaxy MACS 2129-1, which slowed down and then completely left star formation, upsetting the balance between hot and cold gas.It is noteworthy that our Milky Way, according to one theory, is also a zombie galaxy. By measuring the ages of more than 70,000 stars, scientists have found that the Milky Way has been expanding from center to perimeter for 13.6 billion years, just 200 million years less than the age of the universe itself. It is quite possible that our Galaxy has also "outlived its", but we do not know about this, since we are inside and are not able to study all the processes from the outside.