Inside and out of Arp 263

The latest ESA/Webb Picture of the Month is a new, infrared look into the strange final phase of a galactic merger. Arp 263, an irregular galaxy, lies in the constellation Leo at a relatively nearby distance of around 25 million light-years. With this slider tool, compare the infrared and visible-light views of the galaxy.

On the left is Webb’s new image of Arp 263. The thick gas that is so pervasive in the galaxy in Hubble’s image disappears in this one, leaving just a faint glow on the denser right side of the galaxy. Webb’s NIRCam reveals the multitude of pointlike stars in the galaxy’s disrupted disc, as well as the star clusters that have formed in its glowing nebulas. Distant galaxies spring into view as they do in many Webb images, appearing across the background as small orange dots of various shapes.

On the right is Hubble’s visible-light view over Arp 263. Here the star-forming gas is more prominent, both where it lies relatively undisturbed in the galaxy’s core, and where it is actively collapsing to form new stars in the glowing red bubbles. Hubble’s fine resolution shows us some of the exposed star clusters that we can also see in Webb’s image. (The black region visible in the corners appears because this image was cropped and rotated to align with Webb’s image.)