We introduce a novel technique for constraining cosmological parameters and galaxy assembly bias using nonlinear redshiftspace clustering of galaxies. We scale cosmological Nbody simulations and insert galaxies with the SubHalo Abundance Matching extended (SHAMe) empirical model to generate over 175 000 clustering measurements spanning all relevant cosmological and SHAMe parameter values. We then build an emulator capable of reproducing the projected galaxy correlation function at the monopole, quadrupole, and hexadecapole level for separations between $0.1\, h^{1}\, {\rm Mpc}$ and $25\, h^{1}\, {\rm Mpc}$. We test this approach by using the emulator and Monte Carlo Markov Chain (MCMC) inference to jointly estimate cosmology and assembly bias parameters both for the MTNG740 hydrodynamic simulation and for a semianalytical model (SAM) galaxy formation built on the MTNG740DM dark matteronly simulation, obtaining unbiased results for all cosmological parameters. For instance, for MTNG740 and a galaxy number density of $n\sim 0.01 h^{3}\, {\rm Mpc}^{3}$, we obtain $\sigma _{8}=0.799^{+0.039}_{0.044}$ and $\Omega _\mathrm{M}h^2= 0.138^{+ 0.025}_{ 0.018}$ (which are within 0.4 and 0.2σ of the MTNG cosmology). For fixed Hubble parameter (h), the constraint becomes $\Omega _\mathrm{M}h^2= 0.137^{+ 0.011}_{ 0.012}$. Our method performs similarly well for the SAM and for other tested sample densities. We almost always recover the true amount of galaxy assembly bias within 1σ. The best constraints are obtained when scales smaller than $2\, h^{1}\, {\rm Mpc}$ are included, as well as when at least the projected correlation function and the monopole are incorporated. These methods offer a powerful way to constrain cosmological parameters using galaxy surveys.
 Award ID(s):
 1716131
 NSFPAR ID:
 10286739
 Date Published:
 Journal Name:
 Monthly Notices of the Royal Astronomical Society
 Volume:
 491
 Issue:
 3
 ISSN:
 00358711
 Page Range / eLocation ID:
 4116 to 4130
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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