Spiral galaxies grow from within

By happy coincidence group of Hawaiian and French astronomers succeeded in resolving a long-standing debate about how spiral galaxies formed.

This accident was a gravitational lens as a galactic cluster, located between us and the distant spiral galaxy located at a distance from us 9.3 billion years. "Lens" has increased its brightness by 22 times, which has allowed her to study in detail the range and structure.

Until now, scientists could not agree among themselves as to how is it that spiral galaxies are formed. The dispute could resolve one of the main characteristics of the galaxy — metallizm spirals, then, how the metal content from the center to the outskirts (astronomers call metals all chemical elements other than hydrogen and helium)

Metals are generated in stars and ejected them into space. Since stars are concentrated in the center, then, of course, in the center of metals than in the suburbs. For example, in spirals metallizm Milky Way is reduced by 35% for every 10 000 light-years (the diameter of the disk of our Galaxy is known to 120,000 light years). But our galaxy not young, and how was it spirals or spiral galaxy similar "gradient metallizma" at a young age, could shed light on how galaxies are formed.

Having taken the increased gravitational lens galaxies in the constellation Leo, and seeing her in the days when she was young, scientists were able to this gradient for it to count. It turned out that at that time the metal content in its coils decreases from the center to the edges much faster — every 10 thousand light years metallizm spirals fell by 68%.

It speaks well for a long time to show, but does not prove the hypothesis, which says that spiral galaxies grow from within. That, being born in the center, the stars begin to run away from it by thus spirals, heavy metals scattering at the beginning and making them smaller and smaller as they reach the periphery. After billions of years of galaxy ages, the stars are born smaller and the metal content of the spirals is changing is less steep.

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