Environmental effects on subhalo abundance and internal density profiles

In the study of structure formation, properties of dark matter subhalos offer clues to galaxy evolution and indirect dark matter detection. Using the high-resolution COLOR N-body simulation and a multiscale web classification algorithm based on NEXUS+, we examine how subhalo abundance and internal properties depend on the large-scale environment of host halos. Our findings reveal that hosts in filaments contain 5 to 20\% more subhalos than the cosmic mean, while those in voids show a 25\% deficit. Across all environments, the subhalo mass function shows an exponential cutoff at the high subhalo mass end. Subhalo internal properties vary with environment; subhalos in filaments tend to be up to 10\% more concentrated, whereas those in voids are less concentrated. These results show that cosmic web location significantly influences subhalo populations and dynamics, emphasising the need to include environmental effects in modelling small-scale galaxy formation.