We introduce the idea of an effective dark matter halo catalog in $f(R)$ gravity, which is built using the effective density field. Using a suite of high resolution $N$-body simulations, we find that the dynamical properties of halos, such as the distribution of density, velocity dispersion, specific angular momentum and spin, in the effective catalog of $f(R)$ gravity closely mimic those in the cold dark matter model with a cosmological constant ($\mathrm{\Lambda }\mathrm{CDM}$). Thus, when using effective halos, an $f(R)$ model can be viewed as a $\mathrm{\Lambda }\mathrm{CDM}$ model. This effective catalog therefore provides a convenient way for studying the baryonic physics, the galaxy halo occupation distribution and even semianalytical galaxy formation in $f(R)$ cosmologies.

• Received 8 January 2015

DOI:https://doi.org/10.1103/PhysRevLett.115.071306