Stellar winds regulate growth of galaxies

(Nanowerk News) 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 scientist1 has just revealed – using MUSE,2 an instrument integrated into the European Southern Observatory’s (ESO) Very Large Telescope – the existence of the phenomenon in galaxies which 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 ("Bipolar outflows out to 10 kpc for massive galaxies at redshift z ≈ 1"), show this is a universal process.
morphology of galactic winds
The scientists were able to identify the morphology of galactic winds. In this figure, magnesium atom emissions have been used to trace galactic winds. The flow of matter occurs along the central axis perpendicular to the galactic disc. (Image: Yucheng Guo)
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.
Source: CNRS (Note: Content may be edited for style and length)
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