The James Webb Telescope reveals extremely distant objects behind a gravitational magnifier

The first science image released by the James Webb Space Telescope (JWST) was of a gravitational lens, in particular the galaxy cluster SMACS J0723.3−7327. We used the data from this brand-new telescope to model the mass distribution and lensing effect of SMACS0723 with great accuracy. Acting as a so-called gravitational lens, the foreground galaxy cluster produces both multiple images of background galaxies and magnifies these images. One family of such multiple images belongs to a galaxy, which the model predicts to be at a large distance, i.e. whose light travelled some 13 billion years before reaching the telescope. If confirmed, this will emphasize the importance of accurate gravitational lens models for the identification of distant galaxies and their detailed study.