The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR16 sample: a multi-tracer analysis in Fourier space for measuring the cosmic structure growth and expansion rate

We perform a joint BAO and RSD analysis using the eBOSS DR16 LRG and ELG samples in the redshift range of z ∈ [0.6, 1.1], and detect a RSD signal from the cross power spectrum at a ∼ 4σ confidence level, i.e., fσ8 = 0.317 ± 0.080 at zeff = 0.77. Based on the chained power spectrum, which is a new development in this work to mitigate the angular systematics, we measurement the BAO distances and growth rate simultaneously at two effective redshifts, namely, DM/rd (z = 0.70) = 17.96 ± 0.51, DH/rd (z = 0.70) = 21.22 ± 1.20, fσ8 (z = 0.70) = 0.43 ± 0.05, and DM/rd (z = 0.845) = 18.90 ± 0.78, DH/rd (z = 0.845) = 20.91 ± 2.86, fσ8 (z = 0.845) = 0.30±0.08. Combinedwith BAOmeasurements including those from the eBOSS DR16 QSO and Lyman-α sample, our measurement has raised the significance level of a nonzero ΩΛ to ∼ 11σ. The data product of this work is publicly available at https://github.com/icosmology/eBOSS_DR16_LRGxELG ? Email: gbzhao@nao.cas.cn © 2020 The Authors ar X iv :2 00 7. 09 01 1v 1 [ as tr oph .C O ] 1 7 Ju l 2 02 0