Binary pulsars can be excellent probes of ultra-light dark matter. We consider the scenario where the latter is represented by a spin-2 field. The coherent oscillations of the dark matter field perturb the dynamics of binary systems, leading to secular effects for masses that resonate with the binary systems. For the range $10^{ -23}$eV $\lesssim m \lesssim 10^{ -17}$eV we show that current timing data could potentially constrain the universal coupling strength of dark matter to ordinary matter at the level of $\alpha \simeq 10^{ -5}$.
Categories: astro-ph.HE astro-ph.CO gr-qc hep-ph