Cosmic Web Dependence of Neighbouring Dark Matter Haloes around Low-Mass Hosts in the TNG50 Simulation
Year: 2026
Type: article
Abstract: We investigate whether the population and radial kinematics of neighbouring dark matter haloes around low-mass hosts differ between filament and sheet environments in the TNG50 cosmological hydrodynamical simulation at $z=0$. We select host haloes with $11.0 \le \log_{10}(M_{200c}/[M_\odot\,h^{-1}]) < 11.5$ and construct $192$ filament–sheet host pairs closely matched in host mass and local density. An all-pair host–companion cross-correlation shows that the clustering around filament hosts is stronger than that around sheet hosts by $0.16\pm0.06$ dex over $2 < R/R_{200c} \le 4$, corresponding to a factor of about 1.5. The same qualitative enhancement is recovered when using comoving separations rather than distances scaled by $R_{200c}$, and the integrated contrast remains positive in the spatial-block jackknife realizations. In contrast, the median peculiar radial velocities are broadly similar between environments, and the inward-motion fraction becomes lower around filament hosts beyond approximately $3 R_{200c}$. Filament hosts therefore possess a significantly richer neighbouring-halo population than closely matched sheet hosts, while this excess is not accompanied by stronger coherent radial infall. The clustering enhancement remains robust to variations in the companion-mass threshold and to substantially tighter host mass and local density matching. These results support a persistent association between the cosmic web environment and the neighbouring-halo reservoir around low-mass hosts in TNG50.
Authors: Wenxiao Xu, Tianchi Zhang, yirong Ma, Heyu Sun
Institution: Chongqing University of Posts and Telecommunications
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7204802828