Growing Along the Cosmic Web: Insights from BCG-Cluster-Filament Alignments in J-PLUS
Stefano Zarattini (Centro de Estudios de Física del Cosmos de Aragón)
Tuesday 28/04/2026 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
In the first part of this talk I will briefly introduce CEFCA and update the status of the J-PLUS and J-PAS surveys, focusing on how they can help your own science and presenting the Open Time Legacy Survey at JST250, a unique opportunity to observe with the 2.5m telescope and the J-PAS filter set your favourite scientific target. In the second part, I will discuss the importance of large-scale alignments, using a sample of 2018 galaxy clusters identified in the RedMaPPer catalogue that are also available in the J-PLUS footprint. For these clusters, we measured the global position angle (P.A.) by modelling the distribution of member galaxies with an elliptical shape. Moreover, we computed the P.A. of each brightest cluster galaxy (BCG) using the GNUASTRO code. We then estimated the excess of aligned BCGs and used the power of J-PLUS to investigate how the properties of the BCGs (stellar mass, global and recent star-formation rate, and dominance) correlate with the alignment signal. Finally, we used the catalogue of filaments and nodes from Chen et al. (2016) to study the alignment between clusters/BCGs and their closest cosmic filaments. We find an excess of small P.A. differences between BCGs and clusters, thus confirming previous results from the literature. The alignment signal is stronger for massive and dominant central galaxies, suggesting that this result is more closely linked to the intrinsic properties of the BCGs than to those of the host halo. Moreover, an excess of alignment is also found between clusters and filaments. The alignment signal appears to be robust against environmental variations. Specifically, splitting the sample by richness or distance to cosmic structures reveals a persistent excess that does not scale significantly with these quantities. These results suggest that the alignment between BCGs and their host clusters reflects the anisotropic assembly history of the most massive central galaxies, which have preferentially grown along t