See that four dwarf galaxies merge into one in the Hubble image
Image from the Hubble Space Telescope, shared this week by NASA shows an unusual interaction of four dwarf galaxies. There are two small galaxies that are so close together that they look like an object called NGC 1741 at the top of the image. Then there is another cigar-shaped galaxy near the right and a fourth galaxy in the lower left corner, which is connected to the other three by a stream of young stars.
Together, the four galaxies form a set called Hickson Compact Group 31, or HCG 31. The group is located 166 million light-years from Earth, which is relatively close to seeing interacting dwarf galaxies. The galaxies are now so close to each other, 75,000 light-years apart, that all four would fit in the Milky Way.
This image is a reworked version of an image originally released in 2010 that has been processed to bring out the star-forming regions in the group. As the gravitational forces of the galaxy’s mass interact, it stimulates the formation of stars that glow blue when they are young.
The fusion of dwarf galaxies is usually seen very far away, which means they are very old, but this group is relatively young. Astronomers have been able to use Hubble data to regain their positions and see when galaxies began to interact, hundreds of millions of years ago, and predict when they will eventually merge.
“This is a clear example of a group of galaxies on the way to merging because there is so much gas that will mix everything,” said study lead author Sarah Gallagher in statement when the image was released.
“Galaxies are relatively small, comparable in size to the Large Magellanic Cloud, a satellite galaxy on our Milky Way. Their speeds, measured by previous studies, show that they move very slowly relative to each other, only 134,000 miles per hour (60 kilometers per second). So it is difficult to imagine how this system will not become a single elliptical galaxy in another billion years.
Recommendations of the editors
https://www.digitaltrends.com/space/hubble-four-dwarf-galaxies/
