These images are among the first from Hubble after its return to full science operations. On the left is ARP-MADORE2115-273, a rarely observed example of a pair of interacting galaxies. On the right is ARP-MADORE0002-503, a large spiral galaxy with unusual spiral arms. Most disk galaxies have an even number of spiral arms, but this one has three.
NGC 6240 is a cosmic catastrophe in its final throes. It’s a titanic collision of galaxies throwing distorted tidal tails of stars, gas, and dust and undergoing massive bursts of star formation. The two supermassive black holes in the original galactic cores will also coalesce into a single, even more massive black hole. Eventually, only one large galaxy will remain.
This picture shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock). Its unusual shape is caused by its interactions with the smaller galaxy called IC 4970 that can be seen just above it. The pair are roughly 300 million light-years away from Earth.
NGC 6872 measures over 500,000 light-years across. It’s the second largest spiral galaxy discovered thus far. Our own galaxy, the Milky Way, measures around 100,000 light-years across.
The upper left spiral arm of NGC 6872 appears distorted and is filled with star-forming regions which appear blue on this Hubble image. That may have been be caused by IC 4970 recently (only about 130 million years ago) passing through this spiral arm. Astronomers have noted that NGC 6872 seems to be relatively sparse in terms of free hydrogen, which is the basis material for new stars. It is probable that if it weren’t for its interactions with IC 4970, NGC 6872 might not have been able to produce these new bursts of star formation.
NGC 6052 is a pair of colliding galaxies located about 230 million light-years away in the constellation of Hercules. The pair were first discovered in 1784 by William Herschel, and they were thought to be a single irregular galaxy because of their odd shape. However, NGC 6052 actually consists of two galaxies in the process of colliding.