Galaxy Cluster MS10081-1224
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Galaxy Cluster MS1008.1-1224

April 28, 2005
This photo is a true-colour image of the cluster of galaxies, MS1008.1-1224 , combined from exposures with the FORS1 multi-mode instrument at VLT UT1, in the four optical bands, B (blue; exposure time 4950 sec; image quality 0.60 - 0.85 arcsec), V (green; 5400 sec; 0.50 - 0.75 arcsec), R (red; 5400 sec; 0.45 - 0.75 arcsec) and I (near-infrared; 4050 sec; 0.45 - 0.75). Two small areas were masked because of two bright stars. The field measures about 7 x 7 arcmin2. North is up and East is left.

It shows the intricate structure of this fine cluster and reveal the presence of a substantial number of gravitational effects. The strong gravitational potential of the cluster acts as a gravitational lens and distorts the images of several background galaxies, while magnifying their luminosity. The mapping of this "gravitational shear" and the study of the numerous "gravitational arclets" that are produced by the cluster will allow to determine its mass and mass distribution.

Some of the magnified galaxies may be very distant, lying at very high redshift. For them the cluster works as a "gravitational telescope", facilitating the study of these otherwise very faint primordial galaxies.

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