The relaxed motion of stars and gas in galactic discs is well approximated by a rotational velocity that is a function of radial position only. implying that individual components have lost any information about their prior states. Thermodynamically. such an equilibrium state is a microcanonical ensemble with maximum entropy. https://lecoureures.shop/product-category/course-a-pied-homme-vetements-chandail-long-sleeves-brosse/