Astronomers Confirm Collision Between Nearby Dwarf Galaxies

The Milky Way is not hanging alone in space – several dwarf galaxies are hovering nearby, and one of them has been a particular target of study for astronomers. Using a new space telescope, researchers from the University of Michigan have determined that the Small Magellanic Cloud is flying apart at the seams after a collision of millions of years in the past.

At a distance of about 200,000 light years, the Small Magellanic Cloud (SMC) is visible from Earth's southern hemisphere. This dwarf galaxy is still vastly compared with the scale of Earth with a diameter of 7,000 light years and several hundred million stars. It's an irregular galaxy, but astronomers have long termed that of a central bar structure it could have been a "galaxy spiral barred" in the past. While studying in the Small Magellanic Cloud, the Michigan team may have found out why it's not a spiral galaxy anymore.

The team used the ESA Gaia telescope to track 315 stars in the Small Magellanic Cloud. Gaia is designed to image stars repeatedly over the course of several years to their location and movement. The Small Magellanic Cloud is an entirely self-contained galaxy, so Gaia has the capacity to follow all the significant changes inside it. What makes it a perfect way to study runaway?

There are two main mechanisms that eject stars from a galaxy. A supernova in a binary system can be seen in the process of producing food. A close pass by an object with high gravity can also slingshot a star of a galaxy. Gaia found evidence of both in the Small Magellanic Cloud. However, it is also known that the region of the SMC known as the Wing is moving away from the body. However, all those stars are moving in the same direction.

Gurtina Besla, an astronomer at the University of Arizona, contributed to the study. In the past, his team modeled a collision between the SMC and the Large Magellanic Cloud, which is twice the size. The group predicted that a miss would cause the wing to fly off in a perpendicular direction. Meanwhile, a collision would drag the Wing towards the Large Magellanic Cloud. That's what Gaia shows – The Wing is separating from the SMC and moving in towards the Large Magellanic Cloud.

The team estimates that the two dwarf galaxies collided within the last several hundred million years, but there is still a lot to learn. With data from Gaia and other upcoming telescopes, we'll be able to study this separation in unparalleled detail. We're lucky that the Small Magellanic Cloud is in our galactic neighborhood.

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