University of Bonn | 2022 Aug 05
Signs of disturbance in the dwarf galaxies of one of Earth’s nearest galaxy clusters indicate an alternative gravity theory
Dwarf galaxies are small, faint galaxies that can usually be found in galaxy clusters or near larger galaxies. Because of this, they might be affected by the gravitational effects of their larger companions. “We introduce an innovative way of testing the standard model based on how much dwarf galaxies are disturbed by gravitational 'tides' from nearby larger galaxies”, said Elena Asencio... Tides arise when gravity from one body pulls differently on different parts of another body. These are similar to tides on Earth, which arise because the moon pulls more strongly on the side of Earth which faces the moon.
The Fornax Cluster has a rich population of dwarf galaxies. Recent observations show that some of these dwarfs appear distorted, as if they have been perturbed by the cluster environment. "Such perturbations in the Fornax dwarfs are not expected according to the Standard Model,” said Pavel Kroupa... “This is because, according to the standard model, the dark matter halos of these dwarfs should partly shield them from tides raised by the cluster." ...
The distribution and morphologies of Fornax Cluster
dwarf galaxies suggest they lack dark matter ~ Elena Asencio et al