A peculiar pair of galaxies has been recently caught the attention of the astronomers working with the Hubble space telescope. The pair, called Arp. 116, is made of a giant elliptical galaxy named Messier 60 and a smaller spiral galaxy NCG 4647.
Astronomers working with Hubble have been been trying to determine whether these two galaxies actually interact for a long time. In a pair of galaxies, which interact, a sudden appearance of new stars is often observed. A birth of many new stars is associated with the gravitational interaction, which causes the collapse of the gas clouds in the galaxies interacting. Even though such a burst of new stars has not been observed in Arp. 116, other signs of gravitational interaction were discovered.
The picture below is a great example of how two neighbour galaxies of different types can vary in size, structure and colour. Also, the two galaxies have been included into the Atlas of Peculiar Galaxies by Halton Arp (you can find the online version of the atlas here).
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