Spectacular galaxy merger captured by James Webb Telescope

Using the James Webb Telescope, astronomers captured a spectacular image of a galaxy merger.

The merger of a large spiral galaxy and a smaller elliptical galaxy, also known as Arp 107 , occurred 465 million light-years from Earth in the constellation Leo Minor. The James Webb Space Telescope imaged Arp 107 using its Near Infrared Camera (NIRCam) and Mid Infrared Instrument (MIRI). With these instruments, James Webb discovered a nearly transparent white bridge of stars being torn apart from both galaxies. The star-forming regions of gas and dust are colored orange and red, forming a shape that resembles a smiley face among the stars.

The spiral galaxy of this merger is classified as a Seyfert galaxy , one of the largest groups of "active" galaxies that radiate large amounts of energy from their centers.

Galactic merger. (Photo: NASA).

Named after American astronomer Carl K. Seyfert, Seyfert galaxies tend to be dimmer than galaxies that contain quasars. That means Seyfert galaxies are actually active galaxies that are easier to study using low-energy light, like the infrared light James Webb used to observe the universe.

There are many similarities between Arp 107 and another group of interacting galaxies seen by James Webb – the Cartwwheel galaxies . However, Arp 107 is not exactly the same as the Cartwwheel. This is because the smaller elliptical galaxy in Arp 107 was thrown off-center when it collided with the larger spiral galaxy.

As a result, the spiral galaxy portion of Arp 107 has managed to retain most of its structure except for the distinctive spiral arms, which have been almost completely obliterated.

The colliding galaxies of Arp 107 were observed using only mid-infrared means on the James Webb Space Telescope. (Image: NASA).

Collisions between galaxies like Arp107 can be a double-edged sword when it comes to star formation. In galaxies that are not actively forming stars, mergers can provide new reservoirs of gas, the building blocks of star formation, and compress this gas into the dense state needed to create stars. The downside, according to James Webb, is that collisions can disperse the gas, depriving galaxies of the material needed to form new stars.

The Arp 107 collision observed by the James Webb Telescope is expected to take hundreds of millions of years to complete. When it does, the two galaxies will create a larger, irregularly shaped galaxy.