Marked clustering statistics in f(R) gravity cosmologies

We analyse the two-point and marked correlation functions (mCFs) of haloes and galaxies in three variants of the chameleon f(R) gravity model using N-body simulations, and compare to a fiducial Λ cold dark matter model based on general relativity (GR). Using a halo occupation distribution (HOD) prescription, we populate dark matter haloes with galaxies, where the HOD parameters have been tuned such that the galaxy number densities and the real-space galaxy two-point correlation functions in the modified gravity models match those in GR to within 1-3 per cent. We test the idea that since the behaviour of gravity is dependent on environment, mCFs may display a measurable difference between the models. For this we test marks based on the density field and the Newtonian gravitational potential. We find that the galaxy mCF shows significant differences measured in different models on scales smaller than r ≲ 20 h^-1 Mpc. Guided by simulations to identify a suitable mark, this approach could be used as a new probe of the accelerated expansion of the Universe.