The clustering of the SDSS-IV extended baryon oscillation spectroscopic survey DR16 luminous red galaxy and emission-line galaxy samples: cosmic distance and structure growth measurements using multiple tracers in configuration space

ABSTRACT We perform a multitracer analysis using the complete Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation Spectroscopic Survey (eBOSS) DR16 luminous red galaxy (LRG) and the DR16 emission-line galaxy (ELG) samples in the configuration space, and successfully detect a cross-correlation between the two samples, and find the growth rate to be fσ8=0. 342 ± 0. 085 (∼25 per cent accuracy) from the cross-sample alone. We perform a joint measurement of the baryonic acoustic oscillation (BAO) and redshift space distortion (RSD) parameters at a single effective redshift of zeff = 0. 77, using the autocorrelation and cross-correlation functions of the LRG and ELG samples, and find that the comoving angular diameter distance DM (zeff) /rd = 18. 85 ± 0. 38, the Hubble distance DH (zeff) /rd = 19. 64 ± 0. 57, and fσ8 (zeff) = 0. 432 ± 0. 038, which is consistent with a ΛCDM model at 68\ per\ cent CL. Compared to the single-tracer analysis on the LRG sample, the Figure of Merit of α⊥, α∥, andfσ8 is improved by a factor of 1. 11 in our multitracer analysis, and in particular, the statistical uncertainty of fσ8 is reduced by 11. 6\ per\ cent.