Credit: NASA, ESA, S. Gallagher (The University of Western Ontario), and J. English (University of Manitoba)
Four dwarf galaxies are in the process of colliding, lighting up the sky as new stars come to life, form a graceful, celestial “f.” Or does a galactic gator loom in this image of the interacting galaxies of the Hickson Compact Group 31?
This new picture combines imagery from the Hubble Space Telescope, Spitzer Space Telescope and Galaxy Evolution Explorer (GALEX). The object in the middle, making up the body of the alligator, is two dwarf galaxies that have already merged together. Explore the image. A cigar-shaped galaxy above is curved and warped by the interactions with the other two galaxies Bright streamers of gas and dust pulled from the galaxies drape off to point at the fourth, dimmer member of the group. Bright and massive star clusters have formed along the streamers and where the galaxies come together. These new star clusters are just a few million years old. The hot stars that make up the cluster scorch the area with intense ultraviolet radiation, causing the surrounding gas clouds to glow. The bright star near the center of the image is a foreground star between Earth and the interacting galaxies. Seek out the many background galaxies scattered throughout the image.
Hickson Compact Group 31 is in the galactic neighborhood; relatively close at only 166 million light-years from Earth toward the meandering, northern constellation Eridanus, the River. Astronomers usually see interactions between dwarf galaxies like these billions of light-years away in the early universe. Eventually, in another billion years or so, these galaxies will form a larger elliptical galaxy.