This is a pair of colliding galaxies, presenting an absolutely stunning image. Each of the two spiral galaxies is not so different from our Milky Way. They have spent hundreds of millions of years in a violent cosmic dance. Stars are being ripped from the respective galaxies and flung out into an arc between the two.
Gas clouds are in reddish colors, and the star-forming regions are seen in blue. The Antennae are in starburst mode, which is a phase of very rapid star formation. There are also many prominent dust lanes (dark areas).
Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgement: B. Whitmore ( Space Telescope Science Institute) and James Long (ESA/Hubble)
This is a composite image based on both visible and near-infrared data from the Hubble Space Telescope.
“M63 is an Sb spiral in the direction of Canes Venatici. It was discovered in 1779 by Pierre Mechain, a friend of Charles Messier, who composed the Messier catalog. The nickname of this galaxy, the “Sunflower” galaxy is reasonably obvious, since it has a shape and coloration similar to a sunflower and exhibits beautiful yellow colors as well as blue. The latter are regions with recent ongoing star formation. Its spiral arms were first noticed in the mid-19th century.
The Sunflower galaxy is 37 million light-years distant, and is part of a group of galaxies together with M51.”
A collision of two galaxies caused the unusual appearance of the Blackeye Galaxy. The black area in this galaxy is due to massive amounts of dust on this side of the center. While the stars are all revolving around the galaxy’s center in the same sense, a significant amount of gas in the outer regions is moving in the opposite sense. From this, astronomers deduce that a smaller galaxy collided with M64 in the past, perhaps a billion years ago or more.
There is a boundary where the outer region gas, moving in the opposite sense of the stars, meets gas in the inner region, which moves with the stars. In the boundary region the gas clouds moving in opposite directions are colliding, leading to higher density regions, and new star formation is thus enhanced.
The pink regions are hydrogen gas glowing in the red part of the spectrum after absorbing ultraviolet light from new hot stars.
Image credit: NASA, ESA, and The Hubble Heritage Team (AURA/STScI)