Two galaxies are colliding with one another, some 500 million light-years from Earth. Here's what that looks like.
Both the James Webb space telescope and the Hubble Space Telescope have given us plenty to talk about in the last few weeks. Both telescopes are performing admirably in space, exploring the cosmos and photographing some of the most distant objects ever. But this is by no means a competition. Hubble and Webb have their tasks, and both are unique in their own way. Now, astronomers have pointed the James Webb Space Telescope to a cosmic merger some 500 million light-years from Earth. The James Webb Space Telescope has photographed a pair of galaxies that are in the process of merging. Eventually, such collisions give birth to one giant galaxy. Known to experts as II ZW 96, James Webb’s specific infrared cameras looked back in time to observe the two galaxies collide.
A play of gravity
There is also a menagerie of background galaxies dotted throughout the image, in addition to the wild swirl of the merging galaxies. Since both of these galaxies are in a process of merging, their original forms have been distorted by the gravitational pull of each cosmic object. And this merging chaos is what Webb has now observed. In the lower galaxy, the spiral arms have been twisted by the merger’s gravitational perturbation, connecting the two galaxies’ bright cores. The image also shows bright tendrils of star-forming regions that connect both cores. II ZW 96 is particularly bright at infrared wavelengths because of its star-forming regions, making it an attractive target for Webb.
In particular, II ZW 96 is part of a collection of measurements taken by the Webb Space Telescope that probes galactic evolution in detail. As their name suggests, the galaxies have luminosities more than 100 billion times those of the Sun when observed at infrared wavelengths. Almost immediately after Webb was commissioned, an international team proposed observing complex galactic ecosystems. On the list of priorities were merging galaxies like II ZW 96. In addition to the Hubble Space Telescope, ground-based telescopes and the NASA/ESA have already observed the chosen targets, giving astronomers insight into Webb’s capabilities to reveal how complex galactic environments work. NIRCam – a near-infrared camera – and MIRI – a mid-infrared instrument – were used by Webb during the observation of this merging galaxy pair.