Matter Power Spectrum Emulator for f(R) Modified Gravity Cosmologies

TL;DR

This paper introduces an emulator for the matter power spectrum in f(R) modified gravity models, enabling efficient analysis of small-scale deviations from General Relativity for upcoming large-scale structure surveys.

Contribution

The paper develops a novel emulator for the f(R) Hu-Sawicki modified gravity model, facilitating rapid predictions of power spectrum deviations across parameters and redshifts.

Findings

Emulator accurately predicts power spectrum boosts due to modified gravity.

Demonstrates the emulator's utility in parameter sensitivity, Fisher forecasts, and MCMC analyses.

Highlights the importance of the emulator for future LSST cosmological studies.

Abstract

Testing a subset of viable cosmological models beyond General Relativity (GR), with implications for cosmic acceleration and the Dark Energy associated with it, is within the reach of Rubin Observatory Legacy Survey of Space and Time (LSST) and a part of its endeavor. Deviations from GR-w(z)CDM models can manifest in the growth rate of structure and lensing, as well as in screening effects on non-linear scales. We explore the constraining power of small-scale deviations predicted by the f(R) Hu-Sawicki Modified Gravity (MG) candidate, by emulating this model with COLA (COmoving Lagrangian Acceleration) simulations. We present the experimental design, data generation, and interpolation schemes in cosmological parameters and across redshifts for the emulation of the boost in the power spectra due to Modified Gravity effects. Three preliminary applications of the emulator highlight the sensitivity to cosmological parameters, Fisher forecasting and Markov Chain Monte Carlo inference for a fiducial cosmology. This emulator will play an important role for future cosmological analysis handling the formidable amount of data expected from Rubin Observatory LSST.