High-density behavior of nuclear symmetry energy E_sym(ρ) (top panel) and the corresponding isospin asymmetry profile δ(ρ) in NSs at β equilibrium (bottom panel) as functions of the reduced baryon density ρ/ρ₀ by varying the parameter J_sym within its broad range predicted by nuclear theories while all other EOS parameters are fixed at the values indicated. Taken from Zhang et al. (2018).