A relation between the dark mass of elliptical galaxies and their shape

TL;DR

This study reveals a correlation between dark matter content and ellipticity in medium-sized elliptical galaxies, challenging conventional cosmological models and suggesting shape-related differences in dark matter distribution.

Contribution

The paper identifies a novel correlation between dark matter content and galaxy shape, using multiple methods to ensure robustness and minimize biases.

Findings

Rounder galaxies have significantly less dark matter than flatter ones.

The correlation persists across different measurement techniques.

Results challenge existing models of galaxy formation.

Abstract

We have studied a large number of elliptical galaxies and found a correlation between their dark matter content and the ellipticity of their visible shape. The galaxies were strictly selected so that only typical medium-size elliptical galaxies were considered. Galaxies with unusual characteristics were rejected to minimize point-to-point data scatter and avoid systematic biases. Data from six different techniques of extracting the galactic dark matter content were used to avoid methodological biases. A thorough investigation of the interrelation between attributes of elliptical galaxies was carried out to assess whether the correlation originates from an observational bias, but no such origin could be identified. At face value, the correlation found implies that at equal luminosities, rounder medium-size elliptical galaxies appear to contain less dark matter than flatter elliptical galaxies, e.g. the rounder galaxies are on average four times less massive than the flatter ones. This is puzzling in the context of the conventional model of cosmological structure formation.