By Iain Todd

Published: Sunday, 22 September 2024 at 08:30 AM


The James Webb Space Telescope has captured an image of two galaxies colliding, in the process of merging, producing a strange formation that looks rather like a smiley face.

The galaxy collision, known as Arp 107, is the merging of an elliptical galaxy and a spiral galaxy, and Webb has given astronomers a unique view of the event.

See the James Webb Space Telescope’s latest images

Composite image of galaxy merger Arp 107 captured by James Webb Space Telescope’s NIRCam and MIRI instruments. Click to expand. Credit: NASA, ESA, CSA, STScI

About the Webb Arp 107 image

Arp 107 is 465 million lightyears from Earth in the constellation Leo Minor.

The Webb image shows a huge spiral galaxy (in orange and red) and an elliptical galaxy (seen in white), plus a faint bridge of white stars and gas formed by gravitational interactions between the two.

The image of Arp 107 was produced using data captured by the James Webb Space Telescope’s MIRI (Mid-Infrared Instrument) and NIRCam (Near-Infrared Camera).

Image of galaxy merger Arp 107 captured by James Webb Space Telescope's NIRCam (Near-Infrared Camera). Credit: NASA, ESA, CSA, STScI
Image of galaxy merger Arp 107 captured by James Webb Space Telescope’s NIRCam (Near-Infrared Camera). Click to expand. Credit: NASA, ESA, CSA, STScI

NIRCam data shows stars within both galaxies, and the white bridge of gas and dust connecting the two.

MIRI data of Arp 107 shows shows star-forming regions and dust, as well as the the bright core lit up by a supermassive black hole.

The spiral galaxy is a Seyfert galaxy, a type of active galaxy thought to be powered by a central supermassive black hole.

As this image of shows, the galaxy’s core glows brightly in infrared.

Image of galaxy merger Arp 107 captured by James Webb Space Telescope's MIRI (Mid-Infrared Instrument). Credit: NASA, ESA, CSA, STScI
Image of galaxy merger Arp 107 captured by James Webb Space Telescope’s MIRI (Mid-Infrared Instrument). Click to expand. Credit: NASA, ESA, CSA, STScI

When galaxies collide…

A galaxy collision sounds like a pretty destructive event, but in fact they can be more productive than destructive.

Given the vast distances between stars in galaxies, during a galaxy merger like this, collisions between individual stars are extremely unlikely.

Instead, galaxy collisions can churn up and compress cosmic gas and dust, leading to bouts of star formation.

A Spitzer Space Telescope observation of merging galaxies Arp 107 from 20005 shows just how detailed the Webb image is. Credit: NASA/JPL-Caltech/B. J. Smith (East Tennessee State University)
A Spitzer Space Telescope observation of merging galaxies Arp 107 from 20005 shows just how detailed the Webb image is. Click to expand. Credit: NASA/JPL-Caltech/B. J. Smith (East Tennessee State University)

Yet paradoxically, that gas and dust can also be dispersed across the galaxy, potentially depriving young stars of the ingredients they need to form.

But don’t expect any sort of resolution to this story any time soon. The full merger will only be complete after hundreds of millions of years.

webbtelescope.org