SCALE: Using S-PLUS photometric information to analyse the brightest cluster galaxy alignment with satellite galaxies

Context. Studies of large-scale structures in the Universe reveal that galaxy clusters form in regions of matter overdensity, at the intersection of the filamentary structures that comprise the cosmic web. In this process, satellite galaxies tend to spatially align with the major axis of the brightest cluster galaxy (BCG), a phenomenon influenced by both cluster-scale dynamics and the surrounding large-scale environment. Aims. In this study we investigated the alignment of satellite galaxies relative to the BCG position angle using photometric data from the fifth data release of the Southern Photometric Local Universe Survey (S-PLUS/DR5) to unveil how galaxies evolve under the influence of both local and global conditions. Methods. Using three complementary statistical tests, the Kuiper V, binomial, and Rao’s spacing tests, we explored how the alignment signal varies with BCG and cluster properties. Our sample includes 58 galaxy clusters with spectroscopically confirmed BCGs within the STRIPE-82 region, up to a redshift of z < 0.12. Results. The alignment strength is more pronounced for redder BCGs and brighter BCGs, with the most luminous BCGs presenting the strongest correlation with their satellite distributions. In addition, combining multiple properties, such as BCG colour and luminosity, does not further enhance the alignment signal, as the samples naturally favour BCGs with properties that maximise the effect. Beyond 3 R200, satellite colours become more evolved along the BCG major axis for the reddest BCGs, suggesting preprocessing within large-scale filaments. These findings are further evidence of the role of cluster-scale dynamics and large-scale structure in shaping galaxy alignments.