The network analysis of the cosmic web as a tool to constrain cosmology and cosmic magnetism

Context. The spatial distribution of haloes in the cosmic web encodes a wealth of information about the underlying cosmological model. These haloes can be represented as nodes of a graph, whose structural properties reflect cosmological parameters. Aims. Using our new MAKITRA suite of cosmological magneto-hydrodynamical (MHD) simulations covering a total volume of (300 Mpc) 3 and with 21 physical model variations (including variations of σ 8 and of different models of primordial magnetic fields, PMFs), we aim to investigate the sensitivity of network-based statistics describing the cosmic web variations in cosmological and PMF scenarios. Methods. We focused on several complementary metrics that characterize the spatial distribution of dark and baryonic matter halos: two-point correlation functions, network-centrality statistics, and counts-in-cell (CIC) measurements. We first compared the halo–halo correlation functions across different cosmological models. For the network analysis, we represented halos as vertices of the cosmic web and computed multiple centrality measures, whose cumulative distributions we evaluated for universes with varying PMF strengths. Finally, we quantified halo abundances within randomly placed spheres of fixed radius to assess differences between scenarios. Results. First, we find that the statistics of the centralities of the network can serve as a novel sensitive probe of the cosmological parameter σ 8 . Moreover, we find that this network analysis approach allows us to distinguish the presence of PMFs with an initial strength ≃4 nG from the scenarios with much weaker PMFs.