The cluster of galaxies LCDCS-S001 – II. r' and i' photometry, morphological analysis and improved kinematic parameters

Abstract

We present photometric parameters of the galaxies in the direction of the galaxy cluster LCDCS-S001 and improved kinematic parameters from newspectroscopic observations. From GMOS multi-object spectroscopy, we have been able to confirm a new set of 10 cluster members, resulting in a total 22 objects from previous observations. With these data, a dispersion velocity of σ =887±249 km s-ˡ, a virial radius R200 =0.98±0.22 Mpc and a mass ofM200 = (5.4±2.8)×10 14Mʘ have been derived. From GMOS i' and r' images, we have extracted the individual sources and derived their magnitudes, relative positions and the bulge+disc brightness profile decomposition. We show that the cluster has an elongated morphology along the north–south direction, with ellipticity ε = 0.49 ± 0.14, well represented by a King model with a core radius RC = 283 ± 66 kpc, above the typical core radii of regular clusters. It shows at least one local overdensity, north-west from the cluster centre, very compact and with a very high central density. The i' luminosity function of LCDCS-S001 has an almost flat faint-end, α =−1.16 ± 0.18. As for the constituent galaxies, we have found that a large fraction of the cluster galaxies are late-type systems. Extensive simulations were made in order to verify the validity of our conclusions. We discuss the implication of these results for the evolutionary status of LCDCS-S001 and conclude that this cluster is still dynamically young.