We measure and analyse the bispectrum of the final data release 12 (DR12), galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS ...galaxies. The LOWZ sample contains 361 762 galaxies with an effective redshift of z sub( LOWZ) = 0.32, and the CMASS sample contains 777 202 galaxies with an effective redshift of z sub( CMASS) = 0.57. Combining the power spectrum, measured relative to the line of sight, with the spherically averaged bispectrum, we are able to constrain the product of the growth of structure parameter, f, and the amplitude of dark matter density fluctuations, ..., along with the geometric Alcock-Paczynski parameters, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch, H(z)r sub( s)(z sub( d)), and the angular distance parameter divided by the sound horizon, D sub( A)(z)/r sub( s)(z sub( d)). After combining pre-reconstruction RSD analyses of the power spectrum monopole, quadrupole and bispectrum monopole with post-reconstruction analysis of the BAO power spectrum monopole and quadrupole, we find f(z sub( LOWZ))...(z sub( LOWZ)) = 0.427 plus or minus 0.056, D sub( A)(z sub( LOWZ))/r sub( s)(z sub( d)) = 6.60 plus or minus 0.13, H(z sub( LOWZ))r sub( s)(z sub( d)) = (11.55 plus or minus 0.38)10 super( 3) km s super( -1) for the LOWZ sample, and f(z sub( CMASS))...(z sub( CMASS)) = 0.426 plus or minus 0.029, D sub( A)(z sub( CMASS))/r sub( s)(z sub( d)) = 9.39 plus or minus 0.10, H(z sub( CMASS))r sub( s)(z sub( d)) = (14.02 plus or minus 0.22)10 super( 3) km s super( -1) for the CMASS sample. We find general agreement with previous Baryon Oscillation Spectroscopic Survey DR11 and DR12 measurements. Combining our data set with Planck15 we perform a null test of General Relativity through the ...-parametrization finding ...=0.733..., which is ~2.7... away from the General Relativity predictions. (ProQuest: ... denotes formulae/symbols omitted.)
Abstract
Fibre-fed multi-object spectroscopic surveys, with their ability to collect an unprecedented number of redshifts, currently dominate large-scale structure studies. However, physical ...constraints limit these surveys from successfully collecting redshifts from galaxies too close to each other on the focal plane. This ultimately leads to significant systematic effects on galaxy clustering measurements. Using simulated mock catalogues, we demonstrate that fibre collisions have a significant impact on the power spectrum, P(k), monopole and quadrupole that exceeds sample variance at scales smaller than k ∼ 0.1 h Mpc−1. We present two methods to account for fibre collisions in the power spectrum. The first, statistically reconstructs the clustering of fibre-collided galaxy pairs by modelling the distribution of the line-of-sight displacements between them. It also properly accounts for fibre collisions in the shot-noise correction term of the P(k) estimator. Using this method, we recover the true P(k) monopole of the mock catalogues with residuals of <0.5 per cent at k = 0.3 h Mpc−1 and <4 per cent at k = 0.83 h Mpc−1 – a significant improvement over existing correction methods. The quadrupole, however, does not improve significantly. The second method models the effect of fibre collisions on the power spectrum as a convolution with a configuration space top-hat function that depends on the physical scale of fibre collisions. It directly computes theoretical predictions of the fibre-collided P(k) multipoles and reduces the influence of smaller scales to a set of nuisance parameters. Using this method, we reliably model the effect of fibre collisions on the monopole and quadrupole down to the scale limits of theoretical predictions. The methods we present in this paper will allow us to robustly analyse galaxy power spectrum multipole measurements to much smaller scales than previously possible.
We present baryon acoustic oscillation (BAO) scale measurements determined from the clustering of 1.2 million massive galaxies with redshifts 0.2 < z < 0.75 distributed over 9300 deg super( 2), as ...quantified by their redshift-space correlation function. In order to facilitate these measurements, we define, describe, and motivate the selection function for galaxies in the final data release (DR12) of the SDSS III Baryon Oscillation Spectroscopic Survey (BOSS). This includes the observational footprint, masks for image quality and Galactic extinction, and weights to account for density relationships intrinsic to the imaging and spectroscopic portions of the survey. We simulate the observed systematic trends in mock galaxy samples and demonstrate that they impart no bias on BAO scale measurements and have a minor impact on the recovered statistical uncertainty. We measure transverse and radial BAO distance measurements in 0.2 < z < 0.5, 0.5 < z < 0.75, and (overlapping) 0.4 < z < 0.6 redshift bins. In each redshift bin, we obtain a precision that is 2.7 per cent or better on the radial distance and 1.6 per cent or better on the transverse distance. The combination of the redshift bins represents 1.8 per cent precision on the radial distance and 1.1 per cent precision on the transverse distance. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS.
Abstract
We present high signal-to-noise galaxy–galaxy lensing measurements of the Baryon Oscillation Spectroscopic Survey constant mass (CMASS) sample using 250 deg2 of weak-lensing data from ...Canada–France–Hawaii Telescope Lensing Survey and Canada–France–Hawaii Telescope Stripe 82 Survey. We compare this signal with predictions from mock catalogues trained to match observables including the stellar mass function and the projected and two-dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy–halo connection, robustly predicts a lensing signal that is 20–40 per cent larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of
$S_{\rm 8}=\sigma _{\rm 8} \sqrt{\Omega _{\rm m}/0.3}$
compared to Planck Collaboration XIII reconciles the lensing with clustering. However, given the scale of our measurement (r < 10 h
−1 Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos and modifications to general relativity on ΔΣ and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy–halo connection, the effect of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.
We present a study of the clustering and halo occupation distribution of Baryon Oscillation Spectroscopic Survey (BOSS) CMASS galaxies in the redshift range 0.43 < z < 0.7 drawn from the Final ...SDSS-III Data Release. We compare the BOSS results with the predictions of a halo abundance matching (HAM) clustering model that assigns galaxies to dark matter haloes selected from the large BigMultiDark N-body simulation of a flat Λ cold dark matter Planck cosmology. We compare the observational data with the simulated ones on a light cone constructed from 20 subsequent outputs of the simulation. Observational effects such as incompleteness, geometry, veto masks and fibre collisions are included in the model, which reproduces within 1σ errors the observed monopole of the two-point correlation function at all relevant scales: from the smallest scales, 0.5 h
−1 Mpc, up to scales beyond the baryon acoustic oscillation feature. This model also agrees remarkably well with the BOSS galaxy power spectrum (up to k ∼ 1 h Mpc−1), and the three-point correlation function. The quadrupole of the correlation function presents some tensions with observations. We discuss possible causes that can explain this disagreement, including target selection effects. Overall, the standard HAM model describes remarkably well the clustering statistics of the CMASS sample. We compare the stellar-to-halo mass relation for the CMASS sample measured using weak lensing in the Canada–France–Hawaii Telescope Stripe 82 Survey with the prediction of our clustering model, and find a good agreement within 1σ. The BigMD-BOSS light cone including properties of BOSS galaxies and halo properties is made publicly available.
We model the luminosity-dependent projected and redshift-space two-point correlation functions (2PCFs) of the Sloan Digital Sky Survey (SDSS) Data Release 7 Main galaxy sample, using the halo ...occupation distribution (HOD) model and the subhalo abundance matching (SHAM) model and its extension. All the models are built on the same high-resolution N-body simulations. We find that the HOD model generally provides the best performance in reproducing the clustering measurements in both projected and redshift spaces. The SHAM model with the same halo–galaxy relation for central and satellite galaxies (or distinct haloes and subhaloes), when including scatters, has a best-fitting χ2/dof around 2–3. We therefore extend the SHAM model to the subhalo clustering and abundance matching (SCAM) by allowing the central and satellite galaxies to have different galaxy–halo relations. We infer the corresponding halo/subhalo parameters by jointly fitting the galaxy 2PCFs and abundances and consider subhaloes selected based on three properties, the mass M
acc at the time of accretion, the maximum circular velocity V
acc at the time of accretion, and the peak maximum circular velocity V
peak over the history of the subhaloes. The three subhalo models work well for luminous galaxy samples (with luminosity above L
*). For low-luminosity samples, the V
acc model stands out in reproducing the data, with the V
peak model slightly worse, while the M
acc model fails to fit the data. We discuss the implications of the modelling results.
Current and future large redshift surveys, as the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) or the Dark Energy Spectroscopic Instrument (DESI), will ...use emission-line galaxies (ELGs) to probe cosmological models by mapping the large-scale structure of the Universe in the redshift range 0.6 < z < 1.7. With current data, we explore the halo–galaxy connection by measuring three clustering properties of g-selected ELGs as matter tracers in the redshift range 0.6 < z < 1: (i) the redshift-space two-point correlation function using spectroscopic redshifts from the BOSS ELG sample and VIPERS; (ii) the angular two-point correlation function on the footprint of the CFHT-LS; (iii) the galaxy–galaxy lensing signal around the ELGs using the CFHTLenS. We interpret these observations by mapping them on to the latest high-resolution MultiDark Planck N-body simulation, using a novel (Sub)Halo-Abundance Matching technique that accounts for the ELG incompleteness. ELGs at z ∼ 0.8 live in haloes of (1 ± 0.5) × 1012 h
−1M⊙ and 22.5 ± 2.5 per cent of them are satellites belonging to a larger halo. The halo occupation distribution of ELGs indicates that we are sampling the galaxies in which stars form in the most efficient way, according to their stellar-to-halo mass ratio.
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 ...(eBOSS). This data set includes 148 659 quasars spread over the redshift range 0.8 ≤ z ≤ 2.2 and spanning 2112.9 deg^2. We use the Convolution Lagrangian Perturbation Theory approach with a Gaussian Streaming model for the redshift space distortions of the correlation function and demonstrate its applicability for dark matter haloes hosting eBOSS quasar tracers. At the effective redshift z_eff = 1.52, we measure the linear growth rate of structure fσ_8(z_eff) = 0.426 ± 0.077, the expansion rate $$H(z_{\rm eff})= 159^{+12}_{-13}(r_{{\rm s}}^{\rm fid}/r_{\rm s})\,{\rm {\rm }km s}^{-1} {\rm Mpc}^{-1}$$, and the angular diameter distance $$D_{{\rm A}}(z_{\rm eff})=1850^{+90}_{-115}\,(r_{\rm s}/r_{{\rm s}}^{\rm fid})\,{\rm {\rm }Mpc}$$, where r_s is the sound horizon at the end of the baryon drag epoch and $$r_{{\rm s}}^{\rm fid}$$ is its value in the fiducial cosmology. The quoted uncertainties include both systematic and statistical contributions. The results on the evolution of distances are consistent with the predictions of flat Λ-cold dark matter cosmology with Planck parameters, and the measurement of fσ_8 extends the validity of General Relativity 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.
ABSTRACT
We present cosmic birth (COSMological Initial Conditions from Bayesian Inference Reconstructions with THeoretical models): an algorithm to reconstruct the primordial and evolved cosmic ...density fields from galaxy surveys on the light-cone. The displacement and peculiar velocity fields are obtained from forward modelling at different redshift snapshots given some initial cosmic density field within a Gibbs-sampling scheme. This allows us to map galaxies, observed in a light-cone, to a single high redshift and hereby provide tracers and the corresponding survey completeness in Lagrangian space including tetrahedral tessellation mapping. These Lagrangian tracers in turn permit us to efficiently obtain the primordial density field, making the cosmic birth code general to any structure formation model. Our tests are restricted for the time being to augmented Lagrangian perturbation theory. We show how to robustly compute the non-linear Lagrangian bias from clustering measurements in a numerical way, enabling us to get unbiased dark matter field reconstructions at initial cosmic times. We also show that we can accurately recover the information of the dark matter field from the galaxy distribution based on a detailed simulation. Novel key ingredients to this approach are a higher order Hamiltonian-sampling technique and a non-diagonal Hamiltonian mass matrix. This technique could be used to study the Eulerian galaxy bias from galaxy surveys and could become an ideal baryon acoustic reconstruction technique. In summary, this method represents a general reconstruction technique, including in a self-consistent way a survey mask, non-linear and non-local bias, and redshift-space distortions, with an efficiency about 10 times superior to previous comparable methods.
Abstract
We investigate the potential sources of theoretical systematics in the anisotropic Baryon Acoustic Oscillation (BAO) distance scale measurements from the clustering of galaxies in ...configuration space using the final Data Release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS). We perform a detailed study of the impact on BAO measurements from choices in the methodology such as fiducial cosmology, clustering estimators, random catalogues, fitting templates, and covariance matrices. The theoretical systematic uncertainties in BAO parameters are found to be 0.002 in the isotropic dilation α and 0.003 in the quadrupolar dilation ε. The leading source of systematic uncertainty is related to the reconstruction techniques. Theoretical uncertainties are sub-dominant compared with the statistical uncertainties for BOSS survey, accounting 0.2σstat for α and 0.25σstat for ε (σα, stat ∼ 0.010 and σε, stat ∼ 0.012, respectively). We also present BAO-only distance scale constraints from the anisotropic analysis of the correlation function. Our constraints on the angular diameter distance DA(z) and the Hubble parameter H(z), including both statistical and theoretical systematic uncertainties, are 1.5 per cent and 2.8 per cent at zeff = 0.38, 1.4 per cent and 2.4 per cent at zeff = 0.51, and 1.7 per cent and 2.6 per cent at zeff = 0.61. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are cross-checked with other BAO analysis in Alam et al. The systematic error budget concerning the methodology on post-reconstruction BAO analysis presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.