[SHK2011] J224138.46-094706.2 , the SIMBAD biblio

In archival 2.2m MPG-ESO/WFI data we discovered several mass peaks through weak gravitational lensing, forming a possible supercluster at redshift 0.45. Through wide-field imaging and spectroscopy we aim to identify the supercluster centre, confirm individual member clusters, and detect possible connecting filaments. Through multi-colour imaging with CFHT/Megaprime and INT/WFC we identify a population of early-type galaxies and use it to trace the supercluster network. EMMI/NTT multi-object spectroscopy is used to verify the initial shear-selected cluster candidates. We use weak gravitational lensing to obtain mass estimates for the supercluster centre and the filaments. We identified the centre of the SCL2243-0935 supercluster, MACS J2243-0935, which was found independently by Ebeling et al. (2001ApJ...553..668E, 2010MNRAS.407...83E). We found 13 more clusters or overdensities embedded in a large filamentary network. Spectroscopic confirmation for about half of them is still pending. Three (5-15)h₇₀^–1Mpc filaments are detected, and we estimate the global size of SCL2243 to be 45x15x50h₇₀^–1Mpc, making it one of the largest superclusters known at intermediate redshifts. Weak lensing yields r₂₀₀=(2.06±0.13)h₇₀^–1Mpc and M₂₀₀=(1.54±0.29)x10¹⁵M_☉ for MACS J2243 with M/L=428±82, very similar to results from size-richness cluster scaling relations. Integrating the weak lensing surface mass density over the supercluster network (defined by increased i-band luminosity or g-i colours), we find (1.53±1.01)x10¹⁵M_☉ and M/L=305±201 for the three main filaments, consistant with theoretical predictions. The filaments' projected dimensionless surface mass density κ varies between 0.007-0.012, corresponding to ρ/ρ_crit=10-100 depending on location and de-projection. The greatly varying density of the cosmic web is also reflected in the mean colour of galaxies, e.g. <g-i≥2.27mag for the supercluster centre and 1.80 mag for the filaments. SCL2243 is significantly larger and much more richly structured than other known superclusters such as A901/902 or MS0302 studied with weak lensing before. It is a text-book supercluster with little contamination along the line of sight, making it a perfect sandbox for testing new techniques probing the cosmic web.