Chandra X-ray Image of RDCS 1252.9-2927
The Chandra image of the galaxy cluster RDCS 1252.9-2927 shows emission from 70-million-degree Celsius gas. X-ray data indicate that this cluster formed more than 8 billion years ago and has a mass at least 200 trillion times that of the Sun. It is the most massive cluster ever observed at such an early stage in the evolution of the universe.
Scale: Image is 2 arcmin across.
(Credit: NASA/CXC/ESO/P.Rosati et al.)

VLT Optical & Near-Infrared Image of RDCS 1252.9-2927
This image combines optical and near-infrared (red, yellow, and green) emission from galaxies in the cluster RDCS 1252.9-2927 as taken by the European Southern Observatory's Very Large Telescope (VLT) in Cerro Paranal.
Observations using the VLT provided a precise measurement of the distance to the cluster.
Scale: Image is 2 arcmin across.
(Credit: ESO/VLT/P.Rosati et al.)

HST Optical Image of RDCS 1252.9-2927
This Hubble image reveals the core of the cluster RDCS 1252.9-2927. Dominating the core are a pair of large, reddish elliptical galaxies [near center of image]. Their red color indicates an older population of stars. Most of the stars are at least 1 billion years old. The two galaxies appear to be interacting, and may eventually merge to form a larger galaxy that is comparable to the brightest galaxies seen in present-day clusters. The image was assembled from observations taken between May and June 2002 by the ACS Wide Field Camera.
Scale: Image is 1 arcmin across.
(Credit: NASA/ESA/J.Blakeslee (JHU)/M.Postman (STScI)/P.Rosati (ESO))
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Chandra 3-Color X-ray Image of RDCS 1252.9-2927
This 3-color X-ray image shows a wider field of view (9.6 by 8.1 arcmin) around galaxy cluster RDCS 1252.9-2927 - the largest yellow-green source near the center of the image. Red represents low (0.5-1 keV), green represents medium (1-2 keV) and blue represents high (2-7 keV) energy X-rays. X-ray data indicate that the cluster formed more than 8 billion years ago and has a mass at least 200 trillion times that of the Sun. It is the most massive cluster ever observed at such an early stage in the evolution of the universe.
Scale: Image is 9.6 x 8.1 arcmin.
Credit: NASA/CXC/ESO/P.Rosati et al.

Chandra X-ray/Optical Image with Scale Bar
Scale bar = 20 arcsec
(Credit: X-ray: NASA/CXC/ESO/P.Rosati et al.; Optical: ESO/VLT/P.Rosati et al.)