Spiral galaxies rotate with an angular momentum 5 times larger than the elliptical
The dichotomy is responsible for the angular momentum, which in physics is considered a measure of the size and speed of rotation. In the study it turned out that the angular momentum of rotation of spiral galaxies is 5 times higher than elliptical ones. The results were obtained from observations of the amount of gas that fell into the central region of a developing galaxy, where the stars are born the most.
As a result, in the elliptical type only 40% of the available gas enters the central section. In addition, this star formation has a low angular momentum. This situation is very different from the spirals, where not only gas, but also higher angular momentum. To understand, it was necessary to track the history of the formation of several objects. Found out that the elliptical most of the stars create in a rapid collapse. It is believed that due to the powerful outflow of gas caused by supernova explosions, this process stopped at an early stage. But the spirals everything happened slowly, and the stars followed the development of the universe with age. Up to this point, it was believed that elliptical galaxies were formed by the fusion of stellar disks. But ALMA observations questioned this question.
Power ALMA allows you to penetrate the interstellar dust and see the hidden processes of star formation. As it was believed, in an elliptical type, stars are born rapidly due to a dissipative collapse in central regions. It takes about a billion years and star formation ceases due to the “leakage” of gas. Scientists have also determined that the low angular momentum is due to the nature of the central regions in the process of galactic formation, and does not develop with the environment, as previously assumed.