$R^n$ gravity is kicking and alive: the cases of Orion and NGC 3198
  We analyzed the Rotation Curves of two crucial objects, the Dwarf galaxy Orion and the low luminosity Spiral NGC 3198, in the framework of $R^n$ gravity. We surprisingly found that the no DM power-law f(R) case fits them well, performing much better than $\Lambda$CDM Dark Matter halo models. The level of this unexpected success can be a boost for $R^n$ gravity. 
Paolo Salucci, Christiane Frigerio Martins, Ekaterina Karukes
astro-ph.GA