de Sitter horizon temperature ($T(r)=1/(2\pi R\sqrt{1-r^2/R^2})$)

In units $\hslash =c=k_B=1$, the central inertial observer has temperature $1/(2\pi R)$. The Tolman temperature law redshifts it to the displayed static-observer value. Its acceleration satisfies $4{\pi }^2{T}^2=a^2+R^{-2}$. Near the horizon the temperature approaches $a/(2\pi )$, as predicted by the Unruh effect; at the center temperature remains nonzero despite vanishing acceleration.