Galaxies eject cosmic matter into their immediate surroundings in the form of galactic winds, according to a study published on Wednesday by researchers who observed the phenomenon for the first time in a study of a large sample of star clusters, Agerpres reported with reference to AFP.

The MUSE instrument on the European Very Large Telescope (VLT), located in Chile, made it possible to observe this phenomenon for the first time in a galaxy seen from its edge two years ago.

From the central part of its galactic disk, two cones of matter-saturated gas could be seen, which were galactic winds, blasting out perpendicularly from either side.

“We can now generalize this observation to a large number of structures,” said Nicolas Bouchet, an astrophysicist at the Center for Astrophysical Research in Lyon.

The French researcher, who was already at the origins of the observations made two years ago, is one of the lead authors of a study published in the journal Nature, which concluded that the phenomenon of galactic winds appears to be “current” in massive galaxies. .

Explosions of massive stars

Numerous researchers from scientific institutes around the world, mainly in Europe, observed a sample of more than 160 galaxies, viewed from the side or from the front. Located more than 7 billion light-years away, they witness a universe that was then about half its current age.

The MUSE instrument, a full-field spectroscope, makes it possible to observe the signature of chemical elements in extremely diffuse clouds of low-density matter.

By using the VLT’s very long exposure time on samples of galaxies, MUSE has been able to map the shape of the winds that have “escaped” from the galaxies, revealing signatures of magnesium atoms.

These winds result from the explosions of supernovae, massive stars that explode at the end of their lives at a rate of between 1 and 10 per century, depending on the type of galaxy,” explained Nicolas Boucher.

“Over millions of years, they combine to form galactic winds,” the French researcher added. These winds mostly exit their galaxy through its frontal region, since that is where the largest number of stars and therefore supernovae are concentrated. (full on Agerpres)

photo: Panom Bounak, Dreamstime.com