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

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 z_eff = 0.77, using the autocorrelation and cross-correlation functions of the LRG and ELG samples, and find that the comoving angular diameter distance D_M(z_eff)/r_d = 18.85 ± 0.38, the Hubble distance D_H(z_eff)/r_d = 19.64 ± 0.57, and fσ₈(z_eff) = 0.432 ± 0.038, which is consistent with a ΛCDM model at $68{\ \rm per\ cent}$ 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 $11.6{\ \rm per\ cent}$ .