Galaxy cluster RCS2 J2327

This image shows the galaxy cluster RCS2 J2327. The mass of the cluster causes both s trong and weak gravitational lensing , which can be used to calculate the mass of the cluster. This image is a composite of observations from the HAWK-I instrument on ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope ’s Advanced Camera for Surveys . It demonstrates an impressively detailed collaborative approach to studying weak lensing in the cosmos.