The richest superclusters. I. Morphology

TL;DR

This study analyzes the morphology of the richest galaxy superclusters using Minkowski functionals and shapefinders, revealing their filamentary shapes and clumpiness, and compares real data with simulations.

Contribution

It introduces a detailed morphological analysis of superclusters using Minkowski functionals and shapefinders, and compares observed structures with model simulations.

Findings

Rich superclusters are elongated, filamentary structures with dense cores.

Supercluster clumpiness varies between bright and faint galaxies, more so in observations.

Supercluster morphology follows a characteristic curve in the shapefinder plane.

Abstract

We study the morphology of the richest superclusters from the catalogues of superclusters of galaxies in the 2dF Galaxy Redshift Survey and compare the morphology of real superclusters with model superclusters in the Millennium Simulation. We use Minkowski functionals and shapefinders to quantify the morphology of superclusters: their sizes, shapes, and clumpiness. We generate empirical models of simple geometry to understand which morphologies correspond to the supercluster shapefinders. We show that rich superclusters have elongated, filamentary shapes with high-density clumps in their core regions. The clumpiness of superclusters is determined using the fourth Minkowski functional $V_3$. In the $K_1$-$K_2$ shapefinder plane the morphology of superclusters is described by a curve which is characteristic to multi-branching filaments. We also find that the differences between the fourth Minkowski functional $V_3$ for the bright and faint galaxies in observed superclusters are larger than in simulated superclusters.