Witnessing the formation of a galaxy cluster II. Photometric and Spectroscopyc Evidence of Substructures In Rx J1124,3-1700 ([Vmf98]102) at Z~0.41

NILO CASTELLÓN, JOSÉ LUIS; ALONSO, MARÍA VICTORIA; CUEVAS, HECTOR; CARRASCO, E. RODRIGO, RAMÍREZ, AMELIA, GARCÍA LAMBAS, DIEGO.

Observatorio Astronómico de La Plata, La Plata, Argentina

Workshop; Observando con Gemini; 2010

Oficina Gemini Argentina (Mincyt), Asociación Argentina de Astronomía

We present a study of the poor galaxy cluster RX J1124,0-1700(VMF98]102) based on GMOS/Gemini South photometric and spectroscopic observations. Using r' band deep photometry we find evidence of overdensities in the proyected galaxy distribution. At least three substructures are seen in the GMOS Field of View. We obtained spectral data of two of them (North and South substructure). They are separated by ~2000 km/s in the cluster rest of frame with a redshift mean of 0.413 and 0.406. These photometric and dynamic evidences indicate that the cluster [VMF98]102 is an example of a poor cluster in process of accreting sub-structures to become a rich cluster. Future work will be focused in studying the star formation rates (SFR) of the galaxy members, to disentangle the different mechanisms involve in the variation of this phenomenon, and how these mechanisms contribute to the morphological galaxy evolution in low-mass galaxy clusters.