Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | Galaxies
Most galaxies that can be observed today were formed when the universe was between one and two billion years old. In theory, this process is governed by the influx of primordial matter into the galaxies and the ejection of matter via the explosions of massive stars (supernovae) located outside of the galaxies.
The Atacama Large Millimeter/submillimiter Array (ALMA) has allowed the scientists to observe intense CH+ emissions in six distant galaxies of the early universe. Their estimates indicate that the CH+ reservoirs extend over volumes that are larger than the galaxies themselves and that they sometimes contain several times the mass of gases of these galaxies. Highly reactive and therefore unstable, the molecule CH+ is an energy tracer on a galactic scale. The powerful winds resulting from the explosions of stars carry large amounts of energy, generating turbulent movements within large gas reservoirs located on the periphery of galaxies.
According to IRFU researcher Frédéric Bournaud, "this discovery challenges a fundamental theoretical point according to which the material ejected during the supernovae is lost for the original galaxy. It's actually the opposite—these winds partly supply nearby reservoirs and bring turbulence in them, which in turn fosters the formation of new generations of stars."
One of the assets of this scenario is that it justifies why young starburst galaxies have a star formation rate sometimes more than a hundred times higher than current galaxies, and why they continue to form stars after hundreds of millions of years.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.