  We model the back-reaction of a static observer in four-dimensional de Sitter
spacetime by means of a singular $\mathbb Z_q$ quotient. The set of fixed
points of the $\mathbb Z_q$ action consists of a pair of codimension two
minimal surfaces given by 2-spheres in the Euclidean geometry. The introduction
of an orbifold parameter $q>1$ permits the construction of an effective action
for the bulk gravity theory with support on each of these minimal surfaces. The
effective action corresponds to that of Liouville field theory on a 2-sphere
with a finite vacuum expectation value of the Liouville field. The intrinsic
Liouville theory description yields a thermal Cardy entropy that we reintrepret
as a modular free energy at temperature $T=q^{-1}$, whereupon the
Gibbons--Hawking entropy arises as the corresponding modular entropy. We
further observe that in the limit $q\to\infty$ the four-dimensional geometry
reduces to that of global dS$_3$ spacetime, where the two original minimal
surfaces can be mapped to the future and past infinities of dS$_3$ by means of
a double Wick rotation. In this limit, the Liouville theories on the minimal
surfaces become boundary theories at zero temperature whose total central
charge equals that computed using the dS$_3$/CFT$_2$ correspondence.

High Energy Physics - Theory;General Relativity and Quantum Cosmology