Dynamical analyses of z= 0.3, 0.5 galaxy clusters from the SOAR Gravitational Arcs Survey

Abstract

We have performed dynamical analyses of galaxy clusters using optical spectroscopic data. These clusters belong to the SOAR Gravitational Arcs Survey (SOGRAS) (Furlanetto et al. 2013) and are among the richest structures in SDSS stripe 82 with redshifts around z= 0.3 or z= 0.5. For three of those clusters, all with strong lensing features, we carried out individual analysis using Gemini/GMOS data (∼ 25 velocities per cluster). We obtained masses in the range of 3−8×1014 M⊙ and signs of substructure in one of them. For the whole SOGRAS sample (47 clusters) we used SDSS spectroscopic data. Given the low number of velocities per clusters, we stacked the data per redshift and/or richness. Our results indicate that the richest half of the clusters, independently of the redshift, tend to be ∼ 2.5 times more massive than the poorest half. Also we have found that the z= 0.3 and the z= 0.5 clusters have overall masses statistically consistent with each other: 6.3(+3.9 −2.1) and 8.6(+5.2 −1.6) × 1014M⊙ respectively.