The Aemulus Project VI: Emulation of beyond-standard galaxy clustering statistics to improve cosmological constraints

Abstract

There is untapped cosmological information in galaxy redshift surveys in the non-linear regime. In this work, we use the AEMULUS suite of cosmological $N$-body simulations to construct Gaussian process emulators of galaxy clustering statistics at small scales ($0.1-50h^{-1}\mathrm{Mpc}$) in order to constrain cosmological and galaxy bias parameters. In addition to standard statistics -- the projected correlation function $w_{\mathrm{p}}(r_{\mathrm{p}})$, the redshift-space monopole of the correlation function $\hat{I}{¾}_0(s)$, and the quadrupole $\hat{I}{¾}_2(s)$ -- we emulate statistics that include information about the local environment, namely the underdensity probability function $P_{\mathrm{U}}(s)$ and the density-marked correlation function $M(s)$. This extends the model of AEMULUS III for redshift-space distortions by including new statistics sensitive to galaxy assembly bias. In recovery tests, we find that the beyond-standard statistics significantly increase the constraining power on cosmological parameters of interest: including $P_{\mathrm{U}}(s)$ and $M(s)$ improves the precision of our constraints on $\hat{I}{\text{c◯}}_m$ by 27%, $\ddot{I}{ƒ}_8$ by 19%, and the growth of structure parameter, $f\ddot{I}{ƒ}_8$, by 12% compared to standard statistics. We additionally find that scales below $\sim 6h^{-1}\mathrm{Mpc}$ contain as much information as larger scales. The density-sensitive statistics also contribute to constraining halo occupation distribution parameters and a flexible environment-dependent assembly bias model, which is important for extracting the small-scale cosmological information as well as understanding the galaxy-halo connection. This analysis demonstrates the potential of emulating beyond-standard clustering statistics at small scales to constrain the growth of structure as a test of cosmic acceleration.

Published in the Astrophysical Journal; updated to match journal version