The principle of maximum entropy explains the cores observed in the mass distribution of dwarf galaxies

TL;DR

This paper proposes that the cores observed in dwarf galaxy mass distributions naturally arise from the principle of maximum entropy in self-gravitating systems, providing an explanation consistent with observations without requiring new physics or feedback mechanisms.

Contribution

It introduces a thermodynamic explanation based on Tsallis entropy for the core structures in dwarf galaxies, offering an alternative to existing feedback or dark matter modification theories.

Findings

Predicted density profiles match observed cores in dwarf galaxies.

Cores emerge naturally from maximum entropy principles in non-extensive statistical mechanics.

Provides a unified thermodynamic framework for understanding galaxy core structures.

Abstract

Cold Dark Matter (CDM) simulations predict a central cusp in the mass distribution of galaxies. This prediction is in stark contrast with observations of dwarf galaxies which show a central plateau or 'core' in their density distribution. The proposed solutions to this core-cusp problem can be classified into two types. Either they invoke feedback mechanisms produced by the baryonic component of the galaxies, or they assume the properties of the dark matter (DM) particle to depart from the CDM hypothesis. Here we propose an alternative yet complementary explanation. We argue that cores are unavoidable in the self-gravitating systems of maximum entropy resulting from non-extensive statistical mechanics. Their structure follows from the Tsallis entropy, suitable for systems with long-range interactions. Strikingly, the mass density profiles predicted by such thermodynamic equilibrium match the observed cores without any adjustment or tuning. Thus, the principle of maximum Tsallis entropy explains the presence of cores in dwarf galaxies.