From the galactic fountain to single stars
In galaxies, like our Milky Way galaxy, massive stars produce significant winds that blow out of the disc of the galaxy. Some of these stars may explode, sending most of their material rich in metals up and out of the galaxy disc. This hot, metal-enriched gas mills about and cools down before pouring down on the galaxy. Astrophysicists call this phenomenon galactic fountain. It is extremely difficult to simulate such a massive structure while taking into account substructures such as spiral arms, star-forming gas clouds and supernova explosions. However, scientists working on the EU-funded project SFTISM (Star formation in the turbulent interstellar medium) achieved this with the use of an advanced computational technique. The scientists used a method known as adaptive mesh refinement that focuses computational resources on the regions of interest. The galactic fountain flow was approximated at the lowest level of resolution, while areas with apparent star formation were described in higher resolution. A numerical code was developed to utilise multiple processors of high-end computing systems. Large-scale simulations of the galactic fountain were carried out under the Partnership for Advanced Computing in Europe (PRACE) programme and the National Aeronautics and Space Administration (NASA) High-end Computing Programme. The results revealed that supersonic turbulence that originates from supernovae and various other sources lead to the emergence of young stars. In a series of scientific papers, SFTISM scientists compared simulations of large samples of star-forming molecular clouds with observations. Studying the gaseous halos of galaxies was important to understand the various processes that convert gas – the raw material of the Universe – into stars and mass accretion on protostars. SFTISM results provide an unprecedented view of physical processes that contribute to shaping the galactic ecosystem.
Keywords
Galactic fountain, Milky Way, star formation, interstellar medium, high-end computing
