The galaxy JW100 (lower right) features prominently in this image from the NASA/ESA Hubble Space Telescope, its streams of star-forming gas resembling dangling tentacles and earning it the nickname of a ‘jellyfish’ galaxy. Located over 800 million light-years away, in the constellation Pegasus, JW100 is an example of ram pressure stripping – a process by which galaxies plow through the diffuse gas that pervades galaxy clusters, acting like a headwind and stripping gas and dust from the galaxy and creating trailing streamers. The bright elliptical patches in the image are other galaxies in the cluster that hosts JW100. When galaxies encounter this tenuous gas, it has the effect of removing material from the disk of the galaxy, leading to the beautiful jellyfish-like formations seen in this Hubble image.
IC 5338 is an extraordinary elliptical cD galaxy located in a galaxy cluster, noted for the two bright and remarkably bright blotches at the top of the image. These two bright blotches are the core of IC 5338, making it the brightest galaxy in its cluster. Its extended halo is filled with globular star clusters, which likely formed as a result of the galaxy consuming smaller galaxies throughout its life.
Hubble’s Wide Field Camera 3 was used to observe the tendrils of jellyfish galaxies in order to explore star formation under extreme conditions. The data gathered from the observations provided astronomers with a better understanding of the process of star formation throughout the universe, as these tendrils represent star formation in its most extreme state.