Galaxy rotation curves in modified gravity models
  In this work, we investigate the possibility that the galaxy rotation curves
can be explained in the framework of modified gravity models that introduce a
Yukawa term in the gravitational potential. We include dark matter and assume
that the fifth-force couples differently to dark matter and to baryons. We aim
at constraining the modified gravity parameters $\beta$ and $\lambda$, that is,
the strength and the range of the Yukawa fifth force, respectively, using a set
of 40 galaxy rotation curves data from the SPARC catalogue. We include baryonic
gas, disk and bulge components, along with a NFW halo of dark matter. Each
galaxy rotation curve is modeled with three free parameters, beside the two
global Yukawa parameter. We find that the inclusion of the Yukawa term improves
the $\chi^2$ from $680.75$ to $536.23$ for $655$ degrees of freedom. As global
best-fit we obtain $\beta = 0.34\pm0.04$ and $\lambda = 5.61\pm0.91$kpc and a
dark matter content on average 20\% smaller than without the Yukawa term. The
Bayesian evidence in favor of a NFW profile plus Yukawa term is higher than
8$\sigma$ with respect to the standard gravity parametrization.
