Entropy Analysis of Dark Matter Halo Structures

Abstract: In this study, we aim to derive the entropy associated with a dark matter halo modeled using a double (broken) power-law density profile. Our approach is inspired by the pioneering work of Verlinde, who proposed that gravity may not be a fundamental force but rather an emergent phenomenon rooted in entropic principles. To investigate this idea, we examine four different dark matter halo profiles: the Dehnen-type, Hernquist, Jaffe, Plummer sphere, and the perfect sphere. Using these profiles, we derive corresponding entropy expressions and assess their consistency with the second law of thermodynamics, which governs the behavior of entropy in closed systems. Furthermore, to broaden the scope of our analysis, we extend the study to a cosmological context, allowing us to explore how the derived entropy expressions influence the dynamics of the Friedmann equations that describe the evolution of the universe.