Galactic winds enable the exchange of matter between galaxies and their surroundings. In this way, they limit the growth of galaxies, that is, their star formation rate. Although this had already been observed in the local universe, an international research team led by a CNRS scientist has just revealed—using MUSE, an instrument integrated into the European Southern Observatory’s (ESO) Very Large Telescope—the existence of the phenomenon in galaxies that are more than 7 billion years old and actively forming stars, the category to which most galaxies belong. The team’s findings, published in Nature, thus show this is a universal process.

Galactic winds are created by the explosion of massive stars. As they are diffuse and of low density, they are usually hard to spot. To see them, the scientists combined images of more than a hundred galaxies obtained through very long exposure times. By studying magnesium atom emission signals, the team was also able to map the morphology of these winds, which appear as cones of matter perpendicularly ejected from both sides of the galactic plane.

In the future, the researchers hope to measure how far these winds extend and the quantity of matter they transport.

- This press release was provided by CNRS