Twenty five million years ago and 180 light years away, two spiral galaxies collided head-on and kept going. Now, a team of astronomers, led by Analia Smith from the Instituto de Astrofísica de La Plata in Argentina, has recently achieved an impressive image of the aftermath in which we see a pair of colliding galaxies: UGC 12914 and UGC 12915.
Galaxy collisions are incredible events that transform our cosmos and are largely responsible for driving the evolution of the universe. However, the head-on collision between the two galaxies seems to have resulted in a different type of structure: a bridge of highly turbulent material that spans between the two galaxies that has been dubbed the Taffy Galaxies o galaxias Taffy and that they are near the constellation of Pegasus.
In the image captured by the Gemini International Observatory in Hawaii operated by NOIRLab of the National Science Foundation and that we see below these paragraphs, a tenuous bridge composed of narrow molecular filaments can be seen between the two galaxies, in brown, and clumps of hydrogen gas, shown in red (the structure looks like stretching gum).
As they get closer to each other, the satellite galaxy may pull in one of the larger galaxy’s primary spiral arms, knocking it out of its orbit. It is one of the scenarios that can occur in a galaxy collision. It may also be that the satellite galaxy is intersecting with the larger galaxy, causing significant distortions in its own structure. There are more possibilities, but in all of them, the stellar material from both galaxies ends up mixing, and the resulting collection and compression of the material can trigger star formation.
In this case, the galaxy on the right part of the collision is especially interesting: it is difficult to tell from our viewing angle how much of the disk has been disturbed out of plane. Both galaxies are disturbed by their collision and have yellow nuclei, strangely shaped dark dust lanes, scattered star clusters, and interesting streams of stars.
Although we can’t see the radio bridge, we can see evidence of the collision. The sheer violence of this particular bump left the gas too turbulent to settle and collapse into stars. That is why the bridge that spans between the retreating galaxies is empty of star formation despite the clumps of potential stellar material between the filaments.
Although there are still about 5,000 million years to go, We also know that the Andromeda galaxy, the closest spiral galaxy to our Milky Way, which is visible in our night sky (unless you look hard for it), will shine brightly in our sky, getting bigger and bigger as it gets closer to us. , since, although now they are separated by about 2,500 million light years, by this time, the merger of these two galaxies will be a fact.
Slowly but surely, the Andromeda galaxy is heading towards our galaxy at a speed of about 113 kilometers per second. The Milky Way has about 300 billion stars. The Andromeda galaxy around a trillion. In the merger, the stars will change their orbits around the newly released galactic center, but they will not collide with each other. The mighty collision of these two neighboring galaxies is already underway even if we don’t notice it.
- Association of Universities for Research in Astronomy (AURA). “‘Taffy galaxies’ collide, leave behind bridge of star-forming material: Gemini North captures sprawling aftermath of head-on collision between a pair of galaxies.”
- International Gemini Observatory/NOIRLab/NSF/AURA, Image Processing: M. Rodriguez (NSF’s NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab), J. Miller (Gemini Observatory/NSF’s NOIRLab), M. Zamani (NSF’s NOIRLab) & D. de Martin (NSF’s NOIRLab), Acknowledgment: PI: A. S. Castelli (Universidad Nacional de la Plata)