The galaxies, about 250 million light years away in the constellation of Cancer, are in the final stages of collision, forming a single, giant body called NGC 2623.
As the two galaxies drew closer, their mutual gravitational pull ripped huge clouds of gas from each other into their centre, forming one colossal galactic nucleus.
Stretching out from the nucleus, where hundreds of billions of stars have hurtled together, are two long tails of young stars. This is further evidence that they were once two galaxies – the powerful exchange of gas and energy in the merger has kickstarted star formation.
Also visible in the tails, especially the lower, larger tail, are many prominent star clusters, brighter than anything in our own region of space. Filled with very young stars and clouds of gas where stars are born, these may have been formed from debris from the collision falling back into the nucleus.
The collision has created an “active galactic nucleus” (AGN), where the supermassive black hole at the centre of one of the original galaxies attracts matter around it, forming a violently spinning disc. The rapid motion heats up the disc to incredible temperatures, sending vast amounts of radiation into space.
The infrared and X-ray radiation that is given off is detectable by certain telescopes, and allows astronomers to discover more about the collision than they could see using visible light alone.
Story via Science Daily.