The orientations of galaxy groups and formation of the Local Supercluster

TL;DR

This study investigates the orientations of galaxy groups in the Local Supercluster, revealing correlations with neighboring groups and the supercluster center, supporting filamentary formation models consistent with numerical simulations.

Contribution

It provides observational evidence linking galaxy group orientations with large-scale filamentary structures and supercluster formation, aligning with theoretical predictions.

Findings

Galaxy group orientations are correlated with neighboring groups up to 20 Mpc.

Group major axes align with the line between the brightest galaxies and the supercluster center.

Results support filamentary formation models of galaxy groups.

Abstract

We analysed the orientation of galaxy groups in the Local Supercluster (LSC). It is strongly correlated with the distribution of neighbouring groups in the scale till about 20 Mpc. The group major axis is in alignment with both the line joining the two brightest galaxies and the direction toward the centre of the LSC, i.e. Virgo cluster. These correlations suggest that two brightest galaxies were formed in filaments of matter directed towards the protosupercluster centre. Afterwards, the hierarchical clustering leads to aggregation of galaxies around these two galaxies. The groups are formed on the same or similarly oriented filaments. This picture is in agreement with the predictions of numerical simulations.