The Coma SuperCluster –An Evolving “Island Universe”


The galaxy shown above, NGC 4911, lies more than 320 million light-years away in the "Coma Cluster" an evolving supercluster of 1,000 galaxies and islands of stars similar to the Milky Way 320 million light-years away. NASA said the stunning long-exposure picture, titled “Island Universe”, shows the “majestic face-on spiral galaxy” in the northern constellation Coma Berenices amid a sea of stars.

The Coma, one of the densest collections of galaxies in a nearby universe, is thought to be a galactic supercluster in the making, with several subunits in the throes of merging. Astronomers have located a plume of stars (image below) about 500,000 light years  long in the heart of the central cluster — around four times the diameter of the Milky Way. The plume and other objects (including a patch of stars following in the wake of spiral galaxy NGC 4911 as it plunges into the core of the cluster at more than 1,000 km/s and a fourth smaller arc may be tidal debris left galaxy-galaxy or galaxy-cluster collisions within the past several hundred million years. Over time, the plume should fade into the background sea of stars that permeates the Coma Cluster

NGC 4911 contains rich lanes of dust and gas near its center. These are silhouetted against glowing newborn star clusters and iridescent pink clouds of hydrogen, the existence of which indicates ongoing star formation. Hubble has also captured the outer spiral arms of NGC 4911, along with thousands of other galaxies of varying sizes. The high resolution of Hubble's cameras, paired with considerably long exposures, made it possible to observe these faint details.

Cfhplume (1)
NGC 4911 and other spirals near the center of the cluster are being transformed by the gravitational tug of their neighbors. In the case of NGC 4911, wispy arcs of the galaxy's outer spiral arms are being pulled and distorted by forces from a companion galaxy (NGC 4911A), to the upper right. The resultant stripped material will eventually be dispersed throughout the core of the Coma Cluster, where it will fuel the intergalactic populations of stars and star clusters.

The Coma Cluster is home to almost 10,000 galaxies, making it one of the densest collections of galaxies in the nearby universe. It continues to transform galaxies at the present epoch, due to the interactions of close-proximity galaxy systems within the dense cluster. Vigorous star formation is triggered in such collisions.

Galaxies in this cluster are so densely packed that they undergo frequent interactions and collisions. When galaxies of nearly equal masses merge, they form elliptical galaxies. Merging is more likely to occur in the center of the cluster where the density of galaxies is higher, giving rise to more elliptical galaxies.


The Daily Galaxy via NASA/Hubble


"The Galaxy" in Your Inbox, Free, Daily