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