The alignment of satellite systems with cosmic filaments in the SDSS DR12

TL;DR

This study investigates how satellite galaxy systems align with cosmic filaments in the SDSS DR12, revealing significant correlations that suggest satellites are accreted along filaments, with alignment strength depending on proximity to filament spines.

Contribution

It provides new observational evidence of satellite systems aligning with cosmic filaments and explores how this alignment varies with distance from filament spines.

Findings

Satellite systems are preferentially aligned with filament spines.

Alignment strength varies with proximity to filament spines.

Results support the idea of satellite accretion along filaments.

Abstract

Galaxies, as well as their satellites, are known to form within the cosmic web: the large, multi-scale distribution of matter in the universe. It is known that the surrounding large scale structure (LSS) can impact and influence the formation of galaxies, e.g. the spin and shape of haloes or galaxies are correlated with the LSS and the correlation depends on halo mass or galaxy morphology. In this work, we use group and filament catalogues constructed from the SDSS DR12 to investigate the correlation between satellite systems and the large scale filaments they are located in. We find that the distribution of satellites is significantly correlated with filaments, namely the major axis of the satellite systems are preferentially aligned with the spine of the closest filament. Stronger alignment signals are found for the cases where the system away from the filament spine, while systems close to the filament spine show significantly weaker alignment. Our results suggest that satellites are accreted along filaments, which agrees with previous works. The case of which away from the filament spine may help us to understand how the filament forms as well as the peculiar satellite distribution in the Local Universe.