Exploring the Impacts of Accelerated Expansion on Galaxy Dynamics

Abstract

The contribution of this work is an in-depth analysis of the effects induced by the accelerated expansion of the universe on the dynamics of galaxies, paying particular attention to the contribution of dark energy and alternative cosmological models. It analyzes the role that these ingredients play in the formation and evolution of galaxies within hydrodynamical simulations and by using theoretical modeling. It gives, in detail, the rather insignificant contribution of dark energy towards the process involved in galaxy formation, emphasizing that the action takes effect only in relatively late stages of cosmic developments. The role of black hole feedback is critically reviewed and demonstrates its contribution towards the quenching of star formation in high-mass galaxies. The paper also discusses, as an alternative, a theoretical model based on Tsallis entropy, which shows another approach to explaining both cosmic acceleration and the phenomenon of flat galactic rotation curves without the use of traditional dark matter or dark energy. The Grüneisen parameter is also presented as a thermodynamical tool that connects cosmic expansion to condensed matter physics, allowing new insights on the physical processes that underlie galaxy dynamics. Combining these models, in this paper we deepen the knowledge on the complex interaction of forces at play for driving galaxies towards their observed behavior.