A logarithmic intensity scale is used to better show the inner as well as the outer regions of the galaxies in this field. The original frame is a composite of several shorter exposures and encompasses approx. 8000 x 8000 pixels. The high-resolution version included here has been compressed by a factor of four to facilitate file transfer. Note in particular the large numbers of very faint objects in this field, almost exclusively distant galaxies.
North is up and East is left in both photos.
Clusters of galaxies are some of the largest cosmic structures that are kept together by the combined gravitational pull of its constituents. It contains many hundreds of individual galaxies. The most prominent is a large and bright galaxy, close to the center. According to Hubble's law for the expansion of the Universe, this places the cluster at a distance of about 500 million light-years. It is perhaps of a completely different, but still unknown, nature and may possibly interact with visible matter only via the force of gravity.