Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>In this series of papers, we present an emulator-based halo model for the non-linear clustering of galaxies in modified gravity cosmologies. In the first paper, we present emulators for the following halo properties: the halo mass function, concentration–mass relation and halo-matter cross-correlation function. The emulators are trained on data extracted from the forge and bridge suites of N-body simulations, respectively, for two modified gravity (MG) theories: f(R) gravity, and the DGP model, varying three standard cosmological parameters Ωm0, H0, σ8, and one MG parameter, either $\bar{f}_{R0}$ or rc. Our halo property emulators achieve an accuracy of ${\lesssim}1\ \hbox{per cent}$ on independent test data sets. We demonstrate that the emulators can be combined with a galaxy–halo connection prescription to accurately predict the galaxy–galaxy and galaxy–matter correlation functions using the halo model framework.</jats:p>