The Fierz-Pauli theory on curved spacetime at one-loop and its counterterms

We compute the first four heat-kernel coefficients required for the renormalization of Linearized Massive Gravity. We focus on the Fierz-Pauli theory in a curved spacetime, describing the propagation of a massive spin $2$ field in a non-flat background. The background must be on-shell, i.e. must be an Einstein space, in order to ensure a consistent extension of the Fierz-Pauli theory beyond Minkowski space. Starting from the St\"uckelberg formulation with restored gauge invariance, we apply suitable gauge-fixing procedures to simplify the complicated non-minimal kinetic operators of the scalar, vector, and tensor sectors of the theory, reducing them into manageable minimal forms. Using standard techniques, we then compute the Seeley-DeWitt coefficients, with particular emphasis on the fourth coefficient, $a_3(D)$, in arbitrary spacetime dimensions. This result constitutes our main contribution, as it has not been previously reported in full generality in the literature.