We look for possible evidence of a nonminimal coupling (NMC) between dark matter (DM) and gravity using data
from the X-COP compilation of galaxy clusters. We consider a theoretically motivated NMC that may dynamically
arise from the collective behavior of the coarse-grained DM field (e.g., via Bose–Einstein condensation) with
averaging/coherence length LNMC. In the Newtonian limit, the NMC modifies the Poisson equation by a term
LNMC
2 2r proportional to the Laplacian of the DM density itself. We show that this term, when acting as a
perturbation over the standard Navarro–Frenk–White (NFW) profile of cold DM particles, can yield DM halo
density profiles capable of correctly fitting galaxy clusters’ pressure profiles with an accuracy comparable to and, in
some cases, even better than the standard cold DM NFW profile. We also show that the observed relation between
the NMC length scale and the virial mass found in Gandolfi et al. for late-type galaxies is consistent with the
relation we find in the current work, suggesting that the previously determined power-law scaling law holds up to
galaxy cluster mass scales.
