Abell 3192 photographed by Hubble is a complex of two galaxy clusters located in the constellation Eridanus. Due to their huge mass, they exhibit a gravitational lensing effect. This Hubble Image of the Week captures a massive cluster of luminous galaxies first identified as Abell
3192. Like all galaxy clusters, this one is filled with hot gas that emits intense X-rays, and is shrouded in an invisible halo of dark matter.
This Hubble Space Telescope image shows the Abell 3192 galaxy cluster in the constellation Eridanus. It was initially thought to be a single galaxy cluster, but further research revealed that it consists of two separate galaxy clusters, one closer at 2.3 billion light-years away and the other farther away at 5.4 billion light-years away. The more distant galaxy cluster is MCSJ0358.8-2955, located in the center of the image. These clusters are massive and enveloped in dark matter, creating a gravitational lensing effect that distorts the appearance of smaller galaxies behind them. Image source: ESA/Hubble and NASA, G.Smith, H.Ebeling, D.Coe
All this invisible matter -- not to mention the many galaxies visible in this image -- make up so much mass that the galaxy cluster apparently bends the space-time around it, turning it into a gravitational lens. The smaller galaxies behind the cluster twist into long arcs at the edge of the cluster.
This galaxy cluster is located in the constellation Eridanus, but its distance from the Earth is more complicated. Abell 3192 was originally recorded in the 1989 update of the Abell catalog, which was the first catalog of galaxy clusters published in 1958. At the time, Abell 3192 was thought to consist of a cluster of galaxies concentrated at a single distance. However, further study revealed something surprising: the cluster's mass seemed to be densest at two different points, rather than in one.
Subsequent studies revealed that the original Abell Cluster actually consisted of two separate clusters of galaxies - a foreground cluster about 2.3 billion light-years from Earth, and a further cluster about 5.4 billion light-years away. The more distant galaxy cluster, included in the Massive Galaxy Cluster Survey (MCSJ0358.8-2955), is at the center of this image. The masses of these two galaxy clusters are thought to be equivalent to about 30 trillion and 120 trillion times the mass of the Sun respectively. The two largest galaxies at the center of this image are part of MCSJ0358.8-2955; while the smaller galaxy you see here is a hybrid of the two galaxy groups in Abell 3192.