Non-extensive processes associated with heating of the Galactic disc

¹ Departamento de Física, Universidade Federal do Rio Grande do Norte - 59072-970 Natal, RN, Brazil
² Departamento de Física, Universidade Federal do Ceará - Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceará, Brasil
³ INAF- Osservatorio Astrofisico di Catania - Via S. Sofia 78, I-95123, Catania, Italy

Received: 24 June 2020
Accepted: 18 September 2020

Abstract

We analyse the mechanisms ruling galactic disc heating through the dynamics of space velocities U, V and W, extracted from the Geneva-Copenhagen catalogue. To do this, we use a model based on non-extensive statistical mechanics, where we derive the probability distribution functions that quantify the non-Gaussian effects. Furthermore, we find that the deviation q –1 at a given stellar age follows a non-random behaviour. As a result, the q-index behaviour indicates that the vertical component W, perpendicular to the Galactic plane, does not “heat up” at random, which is in disagreement with previous works that attributed the evolution of W to randomness. Finally, our results bring a new perspective to this matter and open the way for studying Galactic kinematic components through the eyes of more robust statistical models that consider non-Gaussian effects.

The authors would like to dedicate this paper to all the victims of the COVID-19 pandemic around the world.