Abstract

Aims. Superclusters are the largest relatively isolated systems in the cosmic web. Using the SDSS BOSS survey, we search for the largest superclusters in the redshift range 0.43 z 0.71. Methods. We generate a luminosity-density field smoothed over 8 h(-1)Mpc to detect the large-scale over-density regions. Each individual over-density region is defined as single supercluster in the survey. We define the superclusters so that they are comparable to the superclusters found in the SDSS main survey. Results. We find a system that we call the BOSS GreatWall ( BGW), which consists of two walls with diameters 186 and 173 h(-1) Mpc and two other major superclusters with diameters of 64 and 91 h (1) Mpc. As a whole, this system consists of 830 galaxies with the mean redshift 0.47. We estimate the total mass to be approximately 2 x 10(17) h(-1) M-circle dot. The morphology of the superclusters in the BGW system is similar to the morphology of the superclusters in the Sloan Great Wall region. Conclusions. The BGW is one of the most extended and massive systems of superclusters found so far in the Universe.