The distant galaxy K20-ID5

This galaxy is located more than 10.5 billion light years away, at which distance high spatial resolution is needed to trace the different locations of the stars and gas. This near infrared image taken with NACO shows that the stars in this galaxy lie within a quite compact region. In contrast, the gas, which was observed with SINFONI, is very extended. This is not always the case: in another galaxy at a similar redshift, NACO and SINFONI observations (see ESO Press Release eso0631) show that the gas and stars lie in the same large disc. Observations like these are both remarkable and exciting. They yield important insights into the evolution of massive galaxies at early cosmological epochs, allowing us to distinguish between outflowing gas, rotating disk galaxies, and chaotic galaxy mergers.