f(R) Cosmology revisited

Understand

We consider a class of metric f(R) modified gravity theories, analyze them in the context of a Friedmann-Robertson-Walker cosmology and confront the results with some of the known constraints imposed by observations.

• In particular, we focus in correctly reproducing the matter and effective cosmological constant eras, the age of the Universe, and supernovae data.
• Our analysis differs in many respects from previous studies.
• First, we avoid any transformation to a scalar-tensor theory in order to be exempted of any potential pathologies (e.g.