The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: N-body mock challenge for the eBOSS emission line galaxy sample

Alam, S., et al.Cosmological growth can be measured in the redshift space clustering of galaxies targeted by spectroscopic surveys. Accurate prediction of clustering of galaxies will require understanding galaxy physics, which is a very hard and highly non-linear problem. Approximate models of redshift space distortion (RSD) take a perturbative approach to solve the evolution of dark matter and galaxies in the universe. In this paper, we focus on extended Baryon Oscillation Spectroscopic (eBOSS) emission line galaxies (ELGs) that live in intermediate mass haloes. We create a series of mock catalogues using haloes from the Multidark and outer rim dark matter only N-body simulations. Our mock catalogues include various effects inspired by baryonic physics such as assembly bias and the characteristics of satellite galaxies kinematics, dynamics, and statistics deviating from dark matter particles. We analyse these mocks using the TNS RSD model in Fourier space and the convolution Lagrangian perturbation theory (CLPT) in configuration space. We conclude that these two RSD models provide an unbiased measurement of RSD within the statistical error of our mocks. We obtain the conservative theoretical systematic uncertainty of $3.3{{\ \rm per\ cent}}$, $1.8{{\ \rm per\ cent}}$, and $1.5{{\ \rm per\ cent}}$ in fσ8, α∥, and α⊥, respectively, for the TNS and CLPT models. We note that the estimated theoretical systematic error is an order of magnitude smaller than the statistical error of the eBOSS ELG sample and hence are negligible for the purpose of the current eBOSS ELG analysis.SA and JAP are supported by the European Research Council through the COSFORM Research Grant (#670193). VGP acknowledges support from the European Union’s Horizon 2020 research and innovation programme (ERC grant #769130) and by the Atracción de Talento Project no. 2019-T1/TIC-12702 granted by the Comunidad de Madrid in Spain. SH and KH acknowledge support under the U.S. Department of Energy contract W-7405-ENG-36 at Argonne National Laboratory. GR acknowledges support from the National Research Foundation of Korea (NRF) through grant 2017R1E1A1A01077508 and No. 2020R1A2C1005655 funded by the Korean Ministry of Education, Science and Technology (MoEST). RP and SE acknowledge support from the French National Research Agency under grants ANR-16-CE31-0021 (ANR eBOSS), ANR-11-LABX-0060 (OCEVU LABEX), and ANR-11-IDEX-0001-02 (A*MIDEX project)