Detalles de publicación

PP 020136

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

Jorge Sanchez Almeida, Ignacio Trujillo, Angel Ricardo Plastino
(1) Instituto de Astrofisica de Canarias, La Laguna, Tenerife, E-38200, Spain, (2) Departamento de Astrofisica, Universidad de La Laguna, (3) CeBio y Departamento de Ciencias B\'asicas, Universidad Nacional del Noroeste de la Prov. de Buenos Aires, UNNOBA, CONICET, Junin, Argentina
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.

 
Aceptado para publicación en A&A Letters | Enviado el 2020-10-05 | Proyecto P/309201