Composition of Galaxies was associated with their position in the cosmic web

(ORDO NEWS) — Galaxies located in the filaments and nodes of a large-scale network of dark matter contain more heavy elements and evolve faster than galaxies that are alone.

At its largest scale, our universe resembles a tangled web: invisible dark matter forms intertwining and intersecting threads along which most clusters of galaxies are concentrated.

This ” cosmic web ” is the basis of the structure of the universe, which largely determines the evolution of everything that is in it. So, quite recently, astronomers discovered that the position of a galaxy in a web of dark matter determines its composition.

Recall that the earliest universe consisted of the lightest elements – primarily hydrogen and with very small amounts of helium and lithium.

All other elements (astronomers do not quite correctly call them metals) were formed later, in the depths of stars, during supernova explosions, and so on. Therefore, younger galaxies and stars usually contain more metals than older ones, which greatly affects their evolution.

Callum Donnan and colleagues at the University of Edinburgh, Scotland, used data from the SDSS survey to estimate the metallicity of interstellar space in a variety of galaxies up to a billion light-years away. It turned out that galaxies located at the nodes of the “cosmic web” contain significantly more heavy elements.

The same, albeit not so pronounced, correlation has been observed for galaxies located on separate threads of the “web” that are stretched between the nodes. The observations were also confirmed by computer simulations.

Scientists attribute this feature to two factors. First, any galaxy exchanges matter with the surrounding intergalactic space.

If it is located in an empty area containing practically no heavy elements, then its metals will be constantly “diluted” with the lightest elements, and the metallicity will be reduced. But a galaxy located next to other galaxies will receive more heavy elements from the outside.

In addition, it seems that galaxies located in the nodes of the “cosmic web” are evolving faster. After all, both dark and ordinary matter form rather dense clusters there, which accelerates the formation of both galaxies and their stars.

And accelerated evolution accelerates the emergence and accumulation of metals in them. As a result, galaxies located in the nodes and threads of the “web” accumulate more heavy elements than the same galaxies, but found themselves in comparative isolation.


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