Purple haze

This Picture of the Week showcases the impressive NGC 3627 galaxy, also known as Messier 66, located approximately 31 million light-years from Earth in the constellation Leo. The image was taken with the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT) in Chile. But why does it have these unusual colours?

This image is a combination of observations conducted in different wavelengths of light. But rather than seeing the stars in this galaxy, as in more classical images, what this image displays is gas ionised by newly-born stars, with hydrogen, oxygen and sulphur shown in red, blue and orange respectively. 

The image was taken as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project, which is using telescopes operating across all wavelengths to make high-resolution observations of nearby galaxies. The goal of the project is to better understand what triggers, boosts or holds back the formation of new stars in different environments.