  Context. Biases in mass measurements of galaxy clusters are one of the major
limiting systematics in constraining cosmology with clusters. Aims. We aim to
demonstrate that the systematics associated with cluster gravitational
potentials are smaller than the hydrostatic mass bias and that cluster
potentials could therefore be a good alternative to cluster masses in
cosmological studies. Methods. Using cosmological simulations of galaxy
clusters, we compute the biases in the hydrostatic mass (HE mass) and those in
the gravitational potential, reconstructed from measurements at X-ray and
millimeter wavelengths. In particular, we investigate the effects of the
presence of substructures and of non-thermal pressure support on both the HE
mass and the reconstructed potential. Results. We find that the bias in the
reconstructed potential (6%) is less than that of the HE mass (13%), and that
the scatter in the reconstructed potential decreases by about 35% with respect
to that in the HE mass. Conclusions. This study shows that characterizing
galaxy clusters by their gravitational potential is a promising alternative to
using cluster masses in cluster cosmology.
