The James Webb Space Telescope has captured the interaction between an elliptical galaxy and a larger spiral galaxy, commonly known as Arp 107. This image is a combined image that combines observations from the Webb Mid-Infrared Imaging Survey Instrument (MIRI) and the Webb Near Infrared Camera (NIRCam).
NIRCam illuminates stars in both galaxies and reveals the connection between them: a transparent, white bridge of stars pulled from both galaxies as they pass. The MIRI data, shown in orange and red, reveals star-forming regions and dust that is composed of soot-like organic molecules known as polycyclic aromatic hydrocarbons. MIRI also provides a snapshot of the bright core of the large spiral where the supermassive black hole is located.
The spiral galaxy is classified as a Seyfert galaxy, one of the two largest groups of active galaxies, along with galaxies that contain quasars. Seyfert galaxies are not as bright and not as distant as quasars, so they are better places to study similar phenomena in lower energy light, such as infrared.
This region is very similar to the Wheel Galaxy, one of the first interacting galaxies observed by Webb. Arp 107 may turn out to be very similar to the Wheel, but because the smaller elliptical galaxy collided with an off-center instead of a direct collision, the spiral galaxy only escaped damage to its spiral arms.
Collisions are not as scary as they seem. Although there has been a lot of star formation in the past, collisions between galaxies can compress gas, improving the conditions necessary for more stars to form. On the other hand, as Webb shows, collisions also disperse a lot of gas, potentially depriving new stars of the material they need to form.
The Webb captured these galaxies in a merger process that will take hundreds of millions of years. As the two galaxies recover from the chaos of their collision, Arp 107 may lose its smile, but it will inevitably transform into something no less interesting for future astronomers to study.
Arp 107 is located 465 million light-years from Earth in the constellation of the Little Lion.
