WITNESSING THE FORMATION OF GALAXY CLUSTERS: PHOTOMETRIC AND SPECTROSCOPIC EVIDENCE OF SUB-STRUCTURES IN RX J1124,3-1700 ([VMF98]102) at z~ 0.41

J.L. NILO CASTELLÓN, M.V. ALONSO,H. CUEVAS, D. GARCÍA LAMBAS ,E. R. CARRASCO, A. RAMÍREZ

Salta

Congreso; 53ª Reunión Anual de la Asociación Argentina de Astronomía; 2010

IATE - UNSa

We present a photometric and spectroscopic study of the poor cluster RX J1124,0-1700 ([VMF98]102) based on GMOS/Gemini South observations. The cluster shows a complex morphology, with a mean redshift of 0,409 and a velocity dispertion of 674,94 km/s. Using deep photometry in the r´ band, we find evidence of overdensities in the projected galaxy distribution, showing at least three sub-structures in the cluster neighborhoods. We obtained spectral data of two of them (North and South sub-structure), showing a separation of about 2000 km/s in the cluster rest of frame. These evidences suggest that the cluster [VMF98]102 is an example of a poor cluster in process of accreting sub-structures to become a rich cluster.