Observations of an unusual galaxy that has become like a giant "snake" as a result of its curvature by a gravitational lens has helped astronomers learn how some of the first stars in the young universe were formed, according to an article published in the journal Nature Astronomy.
“We have long assumed that the giant clusters of gas thousands of light years long, where the first stars of the Universe were born, actually consisted of many small and unconnected 'stellar nurseries'. We are incredibly lucky that we were able to confirm these assumptions with the help of images obtained thanks to the "cosmic snake", says Valentina Tamburello from the University of Zurich (Switzerland).
It is believed that any accumulation of matter of large mass, including dark matter, interacts with light and causes its rays to bend, as do ordinary optical lenses. Scientists call this effect gravitational lensing. In some cases, the curvature of space helps astronomers see ultra-distant objects - the first galaxies in the Universe and their quasar cores - that would have been inaccessible for observation from Earth without gravitational "increase".
If two quasars, galaxies or other objects are located one after the other for observers on Earth, an interesting thing occurs - the light of a more distant object will split when passing through the gravitational lens of the first. Because of this, we will see not two, but five bright points, four of which will be light “copies” of a more distant object.
This structure is often referred to as the "Einstein Cross" due to the fact that its existence is predicted by the theory of relativity. Most importantly, the same theory says that each copy of an object will be a “photograph” of a quasar, galaxy, or supernova at different periods of their life due to the fact that their light spent different amounts of time to exit the gravitational lens.
One of the most striking examples of such lenses is the cluster of galaxies MACSJ1206 in the constellation Virgo, better known among astronomers as the "cosmic serpent". It got its name from the fact that the attraction of this group of "star metropolises" bends the light of an even more distant galaxy in such a way that it turned into a strip of light, similar to a giant snake.
Its "mirror" reflections, as noted by Tamburello and her colleagues, have a normal, undistorted shape, which allowed scientists to use this "snake" to study how a stellar nursery works in an ancient galaxy, and test popular theories today that dust and gas behaved differently in the “young” universe as it does today.
The fact is that images of other gravitational lenses, obtained with the help of Hubble, showed that such galaxies consist of several giant “stellar nurseries” thousands of light years wide and billions of Suns in mass, within which bizarre giant stars are formed, almost completely consisting of pure hydrogen. Neither such accumulations of gas nor such luminaries exist today in principle, which led many cosmologists to believe that completely different conditions could prevail in the early Universe than they do now.
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As observations of the "copies" of the enlarged galaxy have shown, in fact this is not entirely true - the giant clouds of gas found by Hubble are in fact dozens of large "stellar nurseries" 60-90 light-years long, located close to each other. friend. Their mass is much more modest - they are only tens of millions of times heavier than the Sun, and not billions of times.
As the researchers admit, this is also difficult to explain using modern theories of the evolution of galaxies, but they can also be divided into many small objects that we do not see yet. On the other hand, this does not explain in any way why there is an extremely high density and rate of formation of stars inside these clusters.
Tamburello and her colleagues hope that a new generation of ground-based telescopes, such as the European E-ELT and the scandalous American TMT, will help test this assumption and fully uncover the mystery of why new stars in these galaxies formed hundreds and thousands of times faster than stars are born. in the Milky Way today.
