Chemical effects on the development of the colour--magnitude relation of cluster galaxie

JIMÉNEZ, N. ; CORA, S. A.; BASSIN, L. P.; SMITH CASTELLI, A.; TECCE, T.

Salta

Congreso; LIII Reunión Anual de la Asociación Argentina de Astronomía; 2010

We investigate the development of the colour-magnitude relation(CMR) of cluster galaxies by using a combination of cosmologicalN-body/SPH simulations of galaxy clusters, and asemi-analytic model of galaxy formation and evolution that includesthe effect of feedback of active galactic nuclei (Lagos et al.2008), and an improved estimation of the scalelength of galacticdiscs (Tecce et al. 2010), widening the dynamical range of thestudy by Jim´enez et al. (2009). Our results reinforce the previousconclusions. We compare both simulated and observed CMRsin different bands, finding a very good agreement in all cases. This indicatesthat the physical processes included in the semi-analyticmodel and the adequate tuning of the free parameters involvedhelp reproduce fairly well the main properties of galaxies for furtheruse in our study. In the present work, we perform a statistical analysisof the relative contribution to the stellar mass and metallicity of galaxiesalong the CMR by the different processes involved in their formation andevolution (i.e. quiescent star formation, disc instability events and galaxymergers). The results that emerge from this analysis are found forall simulated clusters, supporting the idea of the universality of the CMRin agreement with observational results.