A galactic fountain

This Picture of the Week, taken with ESO’s Very Large Telescope, captures the galaxy NGC 4383 evolving in a strange way. Gas is flowing from its core at a staggering rate, hurtling from the galaxy at average velocities over 200 km/s, and up to 300 km/s. This mysterious gas eruption has a unique cause: star formation.

Large amounts of stars are being born at the centre of this galaxy. The most massive ones lose mass over their lifetimes through powerful winds, and end up dying in violent supernova explosions. These stellar winds and supernovae drag away some of the galaxy’s gas reservoir: the bright red filaments seen in this image show hydrogen gas ejected out to at least 20 000 light-years from the galaxy. Since this gas is carried away from the galactic core instead of remaining to form the next generation of stars, this process regulates the rate at which stars can form in this galaxy.

A new study led by Adam Watts at the University of Western Australia’s node of the International Centre for Radio Astronomy Research used the Multi Unit Spectroscopic Explorer (MUSE) instrument at the VLT to study this intriguing galaxy. MUSE allowed the team to map the chemical composition and motion of this vast stellar outflow in great detail, providing insights into the mechanisms that created the dramatic outpour seen in this image.