Extreme Canibalism and Strong Gravitational Lense in the Cluster Abell 3827

DIAZ, R.; WEST, M.; BERGMANN, M.; CARRASCO, R.; GOMEZ, P.; LEE, H.; MILLER, B.; TURNER, J.

San Juan, Argentina

Congreso; Reunion Anual de la AAA; 2008

Asociacion Argentina de Astronomia

Abell 3827 is one of the most massive known clusters and at itscenter we observe an extreme example of galactic canibalism: a supergiant elliptical galaxy in its formation process, devoring fivemassive galaxies at the same time.  Using high spatial resolutionGemini+GMOS imagery and multi-object spectroscopy, we derived theredshift (z=0.099) and the radial velocity dispersion of the 55brightest galaxies in the cluster central region(1134 +- 125 km/s).  The estimated virial mass is~ 1E14 M(sun) inside a radius of 300 kpc of the clustercenter.  We have also found features corresponding to a stronggravitational lense, four anular features arranged in an Einstein Ringfrom a galaxy (z=0.2) at double redshift than thecluster, and a fifth arclet feature corresponding to the lensedlight of a farther galaxy (z=0.4).  The possible Einstein Ring is of small angular size and the gravitational lense morphology would confirm that the cluster is indeed very massive and dense.