Constraining f(R) models with cosmic chronometers and the H ii galaxy Hubble diagram

We consider several well-known f(R) cosmological models and constrain their parameters, namely the deviation parameter b and the cosmological parameters Ωm and h. We first obtain analytical approximations for the Hubble rate H(z) and the luminosity distance dL(z) in terms of these parameters, and then test these against the observational expansion rate derived from cosmic chronometers (CCs) and the distance modulus in the H ii galaxy Hubble diagram, obtained in a model-independent way using Gaussian processes. We first optimize the models based solely on the CCs and then repeat this process with a joint analysis using both the CCs and H ii galaxies.