Using an array of space and ground telescopes, including Hubble and Spitzer, astronomers have obtained amazing new images of galaxies colliding in distant space. The collision occurred when the Universe was only half its present age of 13.8 billion years. The picture below shows them as they were at the time of the collision. Massive collision of galaxies created a lot of stars. But how did they capture these images?
Lensing galaxies made it possible to study the otherwise invisible object
It was so far away from the earth that the details would be invisible. But scientists used help of a galaxy-sized magnifying glass to take these photos. It wasn’t actually a magnifying glass. They are called “lensing galaxies,” and are often created by massive structures like galaxy clusters and galaxies. They are so big, and their gravitation effect is so strong that they bend the light around them (image below). As a result, they serve as a natural magnifying glass, making the smaller galaxies behind them visible to scientists.
The images taken by telescopes reveal a gravitationally-induced ring of light around the foreground galaxy that acted as a magnifying glass. What’s more, the lensing galaxy looks like an edge-on disc galaxy, similar to our Milky Way. The European Southern Observatory’s Director for Science, Rob Ivison, said that the combined power of various telescopes and the foreground galaxy’s lensing effects made it possible to observe this distant merger.
What happens when galaxies collide?
Galaxies (known together) H-ATLAS J142935.3-002836 is the object in question. New studies with the help of ‘lensing galaxies’ revealed that this complex and distant object is a product of a distant galactic collision. It was discovered by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in far-infrared wavelengths. The galaxies H-ATLAS J142935.3-002836 look like the well-known and far nearer galactic collision, the Antennae Galaxies.
But the H-ATLAS J142935.3-002836 turns gas that is about 400 times the mass of the Sun into new stars every year. Galaxies don’t crash into each other like speeding cars. When two or more of them collide, they merge into or modify each other’s morphology.