Date Released: Tuesday, September 20, 2005
Source: Case Western Reserve University
Case Western Reserve University astronomers have captured the deepest wide-field image ever of the nearby Virgo cluster of galaxies, directly revealing for the first time a vast, complex web of "intracluster starlight" – nearly 1,000 times fainter than the dark night sky – filling the space between the galaxies within the cluster. The streamers, plumes and cocoons that make up this extremely faint starlight are made of stars ripped out of galaxies as they collide with one another inside the cluster, and act as a sort of "archaeological record" of the violent lives of cluster galaxies.
The new image gives dramatic evidence of the violent life and death of cluster galaxies. Drawn together into giant clusters over the course of cosmic time by their mutual gravity, galaxies careen around in the cluster, smashing into other galaxies, being stripped apart by gravitational forces and even being cannibalized by the massive galaxies which sit at the cluster's heart. The force of these encounters literally pulls many galaxies apart, leaving behind ghostly streams of stars adrift in the cluster, a faint tribute to the violence of cluster life.
The Virgo Cluster of galaxies – so named because it appears in the constellation of Virgo – is the nearest galaxy cluster to the Earth, at a distance of approximately 50 million light years. The cluster contains more than 2,000 galaxies, the brightest of which can be seen with the aide of a small telescope."