The Aemulus Project. V. Cosmological Constraint from Small-scale Clustering of BOSS Galaxies

Journal Article · 11 May 2023 · The Astrophysical Journal

DOI: https://doi.org/10.3847/1538-4357/acc65b · OSTI ID:1884537

Zhai, Zhongxu  ^[1]; Tinker, Jeremy L.  ^[2]; Banerjee, Arka  ^[3]; DeRose, Joseph  ^[4]; Guo, Hong  ^[5]; Mao, Yao-Yuan  ^[6]; McLaughlin, Sean ^[7]; Storey-Fisher, Kate  ^[2]; Wechsler, Risa H.  ^[7]

---

1. Shanghai Jiao Tong University (China); Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai (China); University of Waterloo, ON (Canada)
2. New York University (NYU), NY (United States)
3. Indian Institute of Science Education and Research, Pune (India); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
4. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)
5. Shanghai Astronomical Observatory (China)
6. Rutgers University, Piscataway, NJ (United States)
7. Stanford University, CA (United States). Kavli Institute for Particle Astrophysics & Cosmology; SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

We analyze clustering measurements of BOSS galaxies using a simulation-based emulator of two-point statistics. We focus on the monopole and quadrupole of the redshift-space correlation function, and the projected correlation function, at scales of 0.1 ~ 60 h^-1 Mpc. Although our simulations are based on wCDM with general relativity (GR), we include a scaling parameter of the halo velocity field, γ_f, defined as the amplitude of the halo velocity field relative to the GR prediction. We divide the BOSS data into three redshift bins. After marginalizing over other cosmological parameters, galaxy bias parameters, and the velocity scaling parameter, we find fσ₈(z = 0.25) = 0.413 ± 0.031, fσ₈(z = 0.4) = 0.470 ± 0.026, and fσ₈(z = 0.55) = 0.396 ± 0.022. Compared with Planck observations using a flat Lambda cold dark matter model, our results are lower by 1.9σ, 0.3σ, and 3.4σ, respectively. These results are consistent with other recent simulation-based results at nonlinear scales, including weak lensing measurements of BOSS LOWZ galaxies, two-point clustering of eBOSS LRGs, and an independent clustering analysis of BOSS LOWZ. All these results are generally consistent with a combination of $${\gamma }_{f}^{1/2}{\sigma }_{8}\approx 0.75$$. We note, however, that the BOSS data is well fit assuming GR, i.e., γf = 1. We cannot rule out an unknown systematic error in the galaxy bias model at nonlinear scales, but near-future data and modeling will enhance our understanding of the galaxy–halo connection, and provide a strong test of new physics beyond the standard model.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF)
• Grant/Contract Number: AC02-07CH11359; AC02-76SF00515; 15-WFIRST15-0008; AST-2009291; HST-HF2-51441.001; NAS5-26555; AC02-05CH11231
• OSTI ID: 1884537
• Report Number(s): FERMILAB-PUB-22-612-T; arXiv:2203.08999; oai:inspirehep.net:2054335
• Journal Information: The Astrophysical Journal, Vol. 948, Issue 2; ISSN 0004-637X
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English