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Register a new userThe clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 quasar sample: measurement of the growth rate of structure from the anisotropic correlation function between redshift 0.8 and 2.2
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We present the clustering measurements of quasars in configuration space based on the Data Release 14 (DR14) of the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey. This dataset includes 148,659 quasars spread over the redshift range $0.8leq z leq 2.2$ and spanning 2112.9 square degrees. We use the Convolution Lagrangian Perturbation Theory (CLPT) approach with a Gaussian Streaming (GS) model for the redshift space distortions of the correlation function and demonstrate its applicability for dark matter halos hosting eBOSS quasar tracers. At the effective redshift $z_{rm eff} = 1.52$, we measure the linear growth rate of structure $fsigma_{8}(z_{rm eff})= 0.426 pm 0.077$, the expansion rate $H(z_{rm eff})= 159^{+12}_{-13}(r_{s}^{rm fid}/r_s){rm km.s}^{-1}.{rm Mpc}^{-1}$, and the angular diameter distance $D_{A}(z_{rm eff})=1850^{+90}_{-115},(r_s/r_{s}^{rm fid}){rm Mpc}$, where $r_{s}$ is the sound horizon at the end of the baryon drag epoch and $r_{s}^{rm fid}$ is its value in the fiducial cosmology. The quoted errors include both systematic and statistical contributions. The results on the evolution of distances are consistent with the predictions of flat $Lambda$-Cold Dark Matter ($Lambda$-CDM) cosmology with Planck parameters, and the measurement of $fsigma_{8}$ extends the validity of General Relativity (GR) to higher redshifts($z>1$) This paper is released with companion papers using the same sample. The results on the cosmological parameters of the studies are found to be in very good agreement, providing clear evidence of the complementarity and of the robustness of the first full-shape clustering measurements with the eBOSS DR14 quasar sample.
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We present measurements of the Baryon Acoustic Oscillation (BAO) scale in redshift-space using the clustering of quasars. We consider a sample of 147,000 quasars from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) distributed over 2044 square degrees with redshifts $0.8 < z < 2.2$ and measure their spherically-averaged clustering in both configuration and Fourier space. Our observational dataset and the 1400 simulated realizations of the dataset allow us to detect a preference for BAO that is greater than 2.8$sigma$. We determine the spherically averaged BAO distance to $z = 1.52$ to 3.8 per cent precision: $D_V(z=1.52)=3843pm147 left(r_{rm d}/r_{rm d, fid}right) $Mpc. This is the first time the location of the BAO feature has been measured between redshifts 1 and 2. Our result is fully consistent with the prediction obtained by extrapolating the Planck flat $Lambda$CDM best-fit cosmology. All of our results are consistent with basic large-scale structure (LSS) theory, confirming quasars to be a reliable tracer of LSS, and provide a starting point for numerous cosmological tests to be performed with eBOSS quasar samples. We combine our result with previous, independent, BAO distance measurements to construct an updated BAO distance-ladder. Using these BAO data alone and marginalizing over the length of the standard ruler, we find $Omega_{Lambda} > 0$ at 6.6$sigma$ significance when testing a $Lambda$CDM model with free curvature.
We measure the growth rate and its evolution using the anisotropic clustering of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 14 (DR14) quasar sample, which includes $148,659$ quasars covering the wide redshift range of $0.8 < z < 2.2$ and a sky area of $2112.90$ $rm deg^2$. To optimise measurements we deploy a redshift-dependent weighting scheme, which allows us to avoid binning, and perform the data analysis consistently including the redshift evolution across the sample. We perform the analysis in Fourier space, and use the redshift evolving power spectrum multipoles to measure the redshift space distortion parameter $fsigma_8$ and parameters controlling the anisotropic projection of the cosmological perturbations. We measure $f sigma_8(z=1.52)=0.43 pm 0.05 $ and $dfsigma_8/dz (z=1.52)= - 0.16 pm 0.08$, consistent with the expectation for a $Lambda$CDM cosmology as constrained by the Planck experiment.
We analyze the anisotropic clustering of the Sloan Digital Sky Survey-IV Extended Baryon Oscillation Spectroscopic Survey (eBOSS) Luminous Red Galaxy Data Release 14 (DR14) sample combined with Baryon Oscillation Spectroscopic Survey (BOSS) CMASS sample of galaxies in the redshift range 0.6$<z<$1.0, which consists of 80,118 galaxies from eBOSS and 46,439 galaxies from the BOSS-CMASS sample. The eBOSS-CMASS Luminous Red Galaxy sample has a sky coverage of 1,844 deg$^2$, with an effective volume of 0.9 Gpc$^3$. The analysis was made in configuration space using a Legendre multipole expansion. The Redshift Space Distortion signal is modeled as a combination of the Convolution Lagrangian Perturbation Model and the Gaussian Streaming Model. We constrain the logarithmic growth of structure times the amplitude of dark matter density fluctuations, $f (z_{rm eff})sigma_8(z_{rm eff})=0.454 pm0.139 $, and the Alcock-Paczynski dilation scales which constraints the angular diameter distance $D_A(z_{eff})=1466.5 pm 136.6 (r_s/r_s^{rm fid})$ and $H(z_{rm eff})=105.8 pm 16 (r_s^{rm fid}/r_s) mathrm{km,s^{-1},Mpc^{-1}}$, where $r_s$ is the sound horizon at the end of the baryon drag epoch and $r_s^{rm fid}$ is its value in the fiducial cosmology at an effective redshift $z_{rm eff}=0.72$. These results are in full agreement with the current $Lambda$-Cold Dark Matter ($Lambda$-CDM) cosmological model inferred from Planck measurements. This study is the first eBOSS LRG full-shape analysis i.e. including Redshift-Space Distortions (RSD) simultaneously with the Alcock-Paczynski (AP) effect and the Baryon Acoustic Oscillation (BAO) scale.
We measure the clustering of quasars of the final data release (DR16) of eBOSS. The sample contains $343,708$ quasars between redshifts $0.8leq zleq2.2$ over $4699,mathrm{deg}^2$. We calculate the Legendre multipoles (0,2,4) of the anisotropic power spectrum and perform a BAO and a Full-Shape (FS) analysis at the effective redshift $z{rm eff}=1.480$. The errors include systematic errors that amount to 1/3 of the statistical error. The systematic errors comprise a modelling part studied using a blind N-Body mock challenge and observational effects studied with approximate mocks to account for various types of redshift smearing and fibre collisions. For the BAO analysis, we measure the transverse comoving distance $D_{rm M}(z_{rm eff})/r_{rm drag}=30.60pm{0.90}$ and the Hubble distance $D_{rm H}(z_{rm eff})/r_{rm drag}=13.34pm{0.60}$. This agrees with the configuration space analysis, and the consensus yields: $D_{rm M}(z_{rm eff})/r_{rm drag}=30.69pm{0.80}$ and $D_{rm H}(z_{rm eff})/r_{rm drag}=13.26pm{0.55}$. In the FS analysis, we fit the power spectrum using a model based on Regularised Perturbation Theory, which includes Redshift Space Distortions and the Alcock-Paczynski effect. The results are $D_{rm M}(z_{rm eff})/r_{rm drag}=30.68pm{0.90}$ and $D_{rm H}(z_{rm eff})/r_{rm drag}=13.52pm{0.51}$ and we constrain the linear growth rate of structure $f(z_{rm eff})sigma_8(z_{rm eff})=0.476pm{0.047}$. Our results agree with the configuration space analysis. The consensus analysis of the eBOSS quasar sample yields: $D_{rm M}(z_{rm eff})/r_{rm drag}=30.21pm{0.79}$, $D_{rm H}(z_{rm eff})/r_{rm drag}=3.23pm{0.47}$ and $f(z_{rm eff})sigma_8(z_{rm eff})=0.462pm{0.045}$ and is consistent with a flat $Lambda {rm CDM}$ cosmological model using Planck results.
We develop a new method, which is based on the optimal redshift weighting scheme, to extract the maximal tomographic information of baryonic acoustic oscillations (BAO) and redshift space distortions (RSD) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 14 quasar (DR14Q) survey. We validate our method using the EZ mocks, and apply our pipeline to the eBOSS DR14Q sample in the redshift range of $0.8<z<2.2$. We report a joint measurement of $fsigma_8$ and two-dimensional BAO parameters $D_{rm A}$ and $H$ at four effective redshifts of $z_{rm eff}=0.98, 1.23, 1.52$ and $1.94$, and provide the full data covariance matrix. Using our measurement combined with BOSS DR12, MGS and 6dFGS BAO measurements, we find that the existence of dark energy is supported by observations at a $7.4sigma$ significance level. Combining our measurement with BOSS DR12 and Planck observations, we constrain the gravitational growth index to be $gamma=0.580pm0.082$, which is fully consistent with the prediction of general relativity. This paper is part of a set that analyses the eBOSS DR14 quasar sample.
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