The Hubble space telescope continues to bring to us stunning imagery of celestial objects across the Universe located millions of light years away as if these objects were right here in our Solar System.
The latest set of awe-inspiring images are those of two galaxies merging. The galactic merger has been named the Arp 256 system and is located in the constellation of Cetus (the Sea Monster). The system comprises of two galaxies – a spiral and a barrel shaped galaxy – and is located some 350 million light-years away from Earth.
The nuclei of the two galaxies are still separated by a large distance; however, the distortion in their shapes is impressive. The galaxy in the upper part of the image contains very pronounced tidal tails — long, extended ribbons of gas, dust and stars. The two galaxies still have massive new stellar nurseries that are churning out hot new stars owing to the massive gravitational interactions, which stir up interstellar gas and dust out of which stars are born.
Arp 256 was first catalogued by Halton Arp in 1966, as one of 338 galaxies presented in the aptly-named Atlas of Peculiar Galaxies. The goal of the catalogue was to image examples of the weird and wonderful structures found among nearby galaxies, to provide snapshots of different stages of galactic evolution. These peculiar galaxies are like a natural experiment played out on a cosmic scale and by cataloguing them, astronomers can better understand the physical processes that warp spiral and elliptical galaxies into new shapes.
Many galaxies in this catalogue are dwarf galaxies with indistinct structures, or active galaxies generating powerful jets — but a large number of the galaxies are interacting, such as Messier 51, the Antennae Galaxies, and Arp 256. Such interactions often form streamer-like tidal tails as seen in Arp 256, as well as bridges of gas, dust and stars between the galaxies.