Warped Disk Galaxies. II. From the Cosmic Web to the Galactic Warp

TL;DR

This study explores how the large-scale cosmic web influences galactic warps, revealing correlations between warp types, satellite distributions, and filament proximity, suggesting environmental effects on galaxy morphology.

Contribution

It provides the first statistical analysis linking galactic warp morphology with satellite distribution and cosmic web structure using SDSS data.

Findings

Warped hosts show anisotropic satellite distributions.

S-type warps align with cosmic filaments.

Warp incidence increases near filaments.

Abstract

Galactic warps are common in disk galaxies. While often attributed to galaxy--galaxy tides, a non-spherical dark matter (DM) halo has also been proposed as a driver of disk warping. We investigate links among warp morphology, satellite distribution, and large-scale structure using the Sloan Digital Sky Survey catalog of warped disks compiled by Zee et al.\ (2022). Warps are classified into 244 S and 127 U types, hosting 1,373 and 740 satellites, respectively, and are compared to an unwarped control matched in stellar mass, redshift, and local density. As an indirect, population-level proxy for the host halo's shape and orientation, we analyze the stacked spatial distribution of satellites. Warped hosts show a significant anisotropy: an excess at $45^{\circ}<\phi<90^{\circ}$ (measured from the host major axis), peaking at $P(\phi)\simeq 0.003$, versus nearly isotropic controls. Satellites of S-type warps preferentially align with the nearest cosmic filament, whereas those of U-type warps are more often perpendicular. The incidence of warps increases toward filaments ($r_{\rm fil}<4,{\rm Mpc},h^{-1}$), while the number of satellites around warped hosts remains approximately constant with filament distance, indicating a direct influence of the large-scale environment. We discuss possible links between galactic warps and the cosmic web, including anisotropic tidal fields and differences in evolutionary stage.