scholarly journals Methods for cluster cosmology and application to the SDSS in preparation for DES Year 1 release

2019 ◽  
Vol 488 (4) ◽  
pp. 4779-4800 ◽  
Author(s):  
M Costanzi ◽  
E Rozo ◽  
M Simet ◽  
Y Zhang ◽  
A E Evrard ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Big Bang ◽  
Sloan Digital Sky Survey ◽  
Selection Function ◽  
Mass Relation ◽  
Data Set ◽  
Dark Energy Survey ◽  
Future Work

ABSTRACT We implement the first blind analysis of cluster abundance data to derive cosmological constraints from the abundance and weak lensing signal of redMaPPer clusters in the Sloan Digital Sky Survey (SDSS). We simultaneously fit for cosmological parameters and the richness–mass relation of the clusters. For a flat Λ cold dark matter cosmological model with massive neutrinos, we find $S_8 \equiv \sigma _{8}(\Omega _\mathrm{ m}/0.3)^{0.5}=0.79^{+0.05}_{-0.04}$. This value is both consistent and competitive with that derived from cluster catalogues selected in different wavelengths. Our result is also consistent with the combined probes analyses by the Dark Energy Survey (DES), the Kilo-Degree Survey (KiDS), and with the cosmic microwave background (CMB) anisotropies as measured by Planck. We demonstrate that the cosmological posteriors are robust against variation of the richness–mass relation model and to systematics associated with the calibration of the selection function. In combination with baryon acoustic oscillation data and big bang nucleosynthesis data (Cooke et al.), we constrain the Hubble rate to be h = 0.66 ± 0.02, independent of the CMB. Future work aimed at improving our understanding of the scatter of the richness–mass relation has the potential to significantly improve the precision of our cosmological posteriors. The methods described in this work were developed for use in the forthcoming analysis of cluster abundances in the DES. Our SDSS analysis constitutes the first part of a staged-unblinding analysis of the full DES data set.

scholarly journals The completed SDSS-IV extended baryon oscillation spectroscopic survey: pairwise-inverse probability and angular correction for fibre collisions in clustering measurements

2020 ◽  
Vol 498 (1) ◽  
pp. 128-143 ◽  
Author(s):  
Faizan G Mohammad ◽  
Will J Percival ◽  
Hee-Jong Seo ◽  
Michael J Chapman ◽  
D Bianchi ◽  
...  
Keyword(s):  
Large Scale ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Sloan Digital Sky Survey ◽  
Small Scale ◽  
Distribution Models ◽  
Approximate Methods ◽  
Inverse Probability ◽  
Emission Line Galaxies ◽  
Red Galaxies

ABSTRACT The completed extended Baryon Oscillation Spectroscopic Survey (eBOSS) catalogues contain redshifts of 344 080 quasars at 0.8 < z < 2.2, 174 816 luminous red galaxies between 0.6 < z < 1.0, and 173 736 emission-line galaxies over 0.6 < z < 1.1 in order to constrain the expansion history of the Universe and the growth rate of structure through clustering measurements. Mechanical limitations of the fibre-fed spectrograph on the Sloan telescope prevent two fibres being placed closer than 62 arcsec in a single pass of the instrument. These ‘fibre collisions’ strongly correlate with the intrinsic clustering of targets and can bias measurements of the two-point correlation function resulting in a systematic error on the inferred values of the cosmological parameters. We combine the new techniques of pairwise-inverse probability and the angular upweighting (PIP+ANG) to correct the clustering measurements for the effect of fibre collisions. Using mock catalogues, we show that our corrections provide unbiased measurements, within data precision, of both the projected $\rm {\mathit{ w}_p}\left(\mathit{ r}_p\right)$ and the redshift-space multipole ξ(ℓ = 0, 2, 4)(s) correlation functions down to $0.1\, h^{-1}{\rm Mpc}$, regardless of the tracer type. We apply the corrections to the eBOSS DR16 catalogues. We find that, on scales $s\gtrsim 20\, h^{-1}{\rm Mpc}$ for ξℓ, as used to make baryon acoustic oscillation and large-scale redshift-space distortion measurements, approximate methods such as nearest-neighbour upweighting are sufficiently accurate given the statistical errors of the data. Using the PIP method, for the first time for a spectroscopic program of the Sloan Digital Sky Survey, we are able to successfully access the one-halo term in the clustering measurements down to $\sim 0.1\, h^{-1}{\rm Mpc}$ scales. Our results will therefore allow studies that use the small-scale clustering to strengthen the constraints on both cosmological parameters and the halo occupation distribution models.

scholarly journals Baryon acoustic oscillations signature in the three-point angular correlation function from the SDSS-DR12 quasar survey

2020 ◽  
Vol 492 (3) ◽  
pp. 4469-4476 ◽  
Author(s):  
E de Carvalho ◽  
A Bernui ◽  
H S Xavier ◽  
C P Novaes
Keyword(s):  
Correlation Function ◽  
Angular Correlation ◽  
Statistical Significance ◽  
Acoustic Oscillation ◽  
Sloan Digital Sky Survey ◽  
Similar Data ◽  
Acoustic Oscillations ◽  
Data Set ◽  
A Value ◽  
Angular Correlation Function

ABSTRACT The clustering properties of the Universe at large scales are currently being probed at various redshifts through several cosmological tracers and with diverse statistical estimators. Here we use the three-point angular correlation function (3PACF) to probe the baryon acoustic oscillation (BAO) features in the quasars catalogue from the Sloan Digital Sky Survey Data Release 12, with mean redshift $\overline{z} = 2.225$, detecting the BAO imprint with a statistical significance of $2.9 \sigma$, obtained using lognormal mocks. Following a quasi-model-independent approach for the 3PACF, we find the BAO transversal signature for triangles with sides θ1 = $1{^{\circ}_{.}}0$ and θ2 = $1{^{\circ}_{.}}5$ and the angle between them of α = 1.59 ± 0.17 rad, a value that corresponds to the angular BAO scale $\theta_{\rm BAO}=1{^{\circ}_{.}}82 \pm 0{^{\circ}_{.}}21$, in excellent agreement with the value found in a recent work ($\theta_{\rm BAO}=1{^{\circ}_{.}}77 \pm 0{^{\circ}_{.}}31$) applying the two-point angular correlation function (2PACF) to similar data. Moreover, we performed two types of test: one to confirm the robustness of the BAO signal in the 3PACF through random displacements in the data set, and the other to verify the suitability of our random samples, a null test that in fact does not show any signature that could bias our results.

Combining simulations and physical observations to estimate cosmological parameters

2018 ◽  
Author(s):  
Dave Higdon ◽  
Katrin Heitmann ◽  
Charles Nakhleh ◽  
Salman Habib
Keyword(s):  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Sloan Digital Sky Survey ◽  
Microwave Background ◽  
Statistical Framework ◽  
Sky Survey ◽  
Simulation Results ◽  
Computationally Intensive ◽  
Diverse Data ◽  
The Universe

This article focuses on the use of a Bayesian approach that combines simulations and physical observations to estimate cosmological parameters. It begins with an overview of the Λ-cold dark matter (CDM) model, the simplest cosmological model in agreement with the cosmic microwave background (CMB) and largescale structure analysis. The CDM model is determined by a small number of parameters which control the composition, expansion and fluctuations of the universe. The present study aims to learn about the values of these parameters using measurements from the Sloan Digital Sky Survey (SDSS). Computationally intensive simulation results are combined with measurements from the SDSS to infer about a subset of the parameters that control the CDM model. The article also describes a statistical framework used to determine a posterior distribution for these cosmological parameters and concludes by showing how it can be extended to include data from diverse data sources.

scholarly journals Concordance cosmology?

2020 ◽  
Vol 499 (4) ◽  
pp. 4638-4645
Author(s):  
Youngsoo Park ◽  
Eduardo Rozo
Keyword(s):  
Cold Dark Matter ◽  
Hubble Constant ◽  
Big Bang ◽  
New Physics ◽  
Current Data ◽  
Data Sets ◽  
Late Time ◽  
Acoustic Oscillations ◽  
Dark Energy Survey ◽  
The Difference

ABSTRACT We propose a new intuitive metric for evaluating the tension between two experiments, and apply it to several data sets. While our metric is non-optimal, if evidence of tension is detected, this evidence is robust and easy to interpret. Assuming a flat Lambda cold dark matter (ΛCDM) cosmological model, we find that there is a modest 2.2σ tension between the Dark Energy Survey (DES) Year 1 results and the Planck measurements of the cosmic microwave background. This tension is driven by the difference between the amount of structure observed in the late-time Universe and that predicted from fitting the Planck data, and appears to be unrelated to the tension between Planck and local estimates of the Hubble rate. In particular, combining DES, baryon acoustic oscillations, big bang nucleosynthesis, and supernovae measurements recover a Hubble constant and sound horizon consistent with Planck, and in tension with local distance–ladder measurements. If the tension between these various data sets persists, it is likely that reconciling all current data will require breaking the flat ΛCDM model in at least two different ways: one involving new physics in the early Universe, and one involving new late-time Universe physics.

scholarly journals Quasar X-ray and UV flux, baryon acoustic oscillation, and Hubble parameter measurement constraints on cosmological model parameters

2020 ◽  
Vol 492 (3) ◽  
pp. 4456-4468 ◽  
Author(s):  
Narayan Khadka ◽  
Bharat Ratra
Keyword(s):  
Hubble Parameter ◽  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Joint Analysis ◽  
Model Parameters ◽  
Baryon Acoustic Oscillation ◽  
Current Standard ◽  
X Ray ◽  
Flux Measurements

ABSTRACT We use the 2015 Risaliti and Lusso compilation of 808 X-ray and UV flux measurements of quasars (QSOs) in the redshift range 0.061 ≤ z ≤ 6.28, alone and in conjunction with baryon acoustic oscillation (BAO) and Hubble parameter [H(z)] measurements, to constrain cosmological parameters in six cosmological models. The QSO data constraints are significantly weaker than, but consistent with, those from the H(z) + BAO data. A joint analysis of the QSO + H(z) + BAO data is consistent with the current standard model, spatially flat Λ cold dark matter, but mildly favours closed spatial hypersurfaces and dynamical dark energy.

scholarly journals Cosmic Flow Measurement and Mock Sampling Algorithm of Cosmicflows-4 Tully−Fisher Catalog

2021 ◽  
Vol 922 (1) ◽  
pp. 59
Author(s):  
Fei Qin ◽  
David Parkinson ◽  
Cullan Howlett ◽  
Khaled Said
Keyword(s):  
Flow Measurement ◽  
Cold Dark Matter ◽  
Bulk Flow ◽  
Selection Function ◽  
Local Universe ◽  
Sampling Algorithm ◽  
Model Predictions ◽  
Point Correlation ◽  
Point Correlation Function ◽  
Future Work

Abstract Measurements of cosmic flows enable us to test whether cosmological models can accurately describe the evolution of the density field in the nearby universe. In this paper, we measure the low-order kinematic moments of the cosmic flow field, namely bulk flow and shear moments, using the Cosmicflows-4 Tully−Fisher catalog (CF4TF). To make accurate cosmological inferences with the CF4TF sample, it is important to make realistic mock catalogs. We present the mock sampling algorithm of CF4TF. These mocks can accurately realize the survey geometry and luminosity selection function, enabling researchers to explore how these systematics affect the measurements. These mocks can also be further used to estimate the covariance matrix and errors of the power spectrum and two-point correlation function in future work. In this paper, we use the mocks to test the cosmic flow estimator and find that the measurements are unbiased. The measured bulk flow in the local universe is 376 ± 23 (error) ± 183 (cosmic variance) km s−1 at depth d MLE = 35 Mpc h −1, to the Galactic direction of (l, b) = (298° ± 3°, −6° ± 3°). Both the measured bulk and shear moments are consistent with the concordance Λ Cold Dark Matter cosmological model predictions.

scholarly journals Validation of selection function, sample contamination and mass calibration in galaxy cluster samples

2020 ◽  
Vol 498 (1) ◽  
pp. 771-798
Author(s):  
S Grandis ◽  
M Klein ◽  
J J Mohr ◽  
S Bocquet ◽  
M Paulus ◽  
...  
Keyword(s):  
Cosmological Parameters ◽  
Galaxy Cluster ◽  
Selection Function ◽  
Scaling Relation ◽  
X Ray ◽  
Mass Scaling ◽  
Dark Energy Survey ◽  
Cross Calibration ◽  
Number Counts

ABSTRACT We construct and validate the selection function of the MARD-Y3 galaxy cluster sample. This sample was selected through optical follow-up of the 2nd ROSAT faint source catalogue with Dark Energy Survey year 3 data. The selection function is modelled by combining an empirically constructed X-ray selection function with an incompleteness model for the optical follow-up. We validate the joint selection function by testing the consistency of the constraints on the X-ray flux–mass and richness–mass scaling relation parameters derived from different sources of mass information: (1) cross-calibration using South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) clusters, (2) calibration using number counts in X-ray, in optical and in both X-ray and optical while marginalizing over cosmological parameters, and (3) other published analyses. We find that the constraints on the scaling relation from the number counts and SPT-SZ cross-calibration agree, indicating that our modelling of the selection function is adequate. Furthermore, we apply a largely cosmology independent method to validate selection functions via the computation of the probability of finding each cluster in the SPT-SZ sample in the MARD-Y3 sample and vice versa. This test reveals no clear evidence for MARD-Y3 contamination, SPT-SZ incompleteness or outlier fraction. Finally, we discuss the prospects of the techniques presented here to limit systematic selection effects in future cluster cosmological studies.

scholarly journals The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR14 LRG sample: structure growth rate measurement from the anisotropic LRG correlation function in the redshift range 0.6 < z < 1.0

2019 ◽  
Vol 492 (3) ◽  
pp. 4189-4215 ◽  
Author(s):  
M Icaza-Lizaola ◽  
M Vargas-Magaña ◽  
S Fromenteau ◽  
S Alam ◽  
B Camacho ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Acoustic Oscillation ◽  
Multipole Expansion ◽  
Density Fluctuations ◽  
Sloan Digital Sky Survey ◽  
Redshift Range ◽  
Angular Diameter Distance ◽  
Galaxy Sample ◽  
Growth Rate Measurement

ABSTRACT We analyse 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 &lt; z &lt; 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 1844 deg2, with an effective volume of 0.9 Gpc3. The analysis was made in configuration space using a Legendre multipole expansion. The Redshift Space Distortion signal is modelled 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(zeff)σ8(zeff) = 0.454 ± 0.134, and the Alcock-Paczynski dilation scales which constraints the angular diameter distance $D_A(z_{\mathrm{ eff}})=1466.5 \pm 133.2 (r_s/r_s^{\rm fid})$ and $H(z_{\rm eff})=105.8 \pm 15.7 (r_s^{\rm fid}/r_s) \mathrm{km\, s^{-1}\, Mpc^{-1}}$, where rs 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 zeff = 0.72. These results are in full agreement with the current Λ-Cold Dark Matter (Λ-CDM) cosmological model inferred from Planck measurements. This study is the first eBOSS LRG full-shape analysis i.e. including Redshift Space Distortions simultaneously with the Alcock-Paczynski effect and the Baryon Acoustic Oscillation scale.

scholarly journals A search for cosmological anisotropy using the Lyman alpha forest from SDSS quasar spectra

2019 ◽  
Vol 489 (3) ◽  
pp. 3966-3980
Author(s):  
Evgeny O Zavarygin ◽  
John K Webb
Keyword(s):  
Standard Model ◽  
Initial Conditions ◽  
Neutral Hydrogen ◽  
Big Bang ◽  
Sloan Digital Sky Survey ◽  
Data Set ◽  
Spatially Correlated ◽  
Quasar Spectra ◽  
The Standard Model ◽  
Systematic Effects

ABSTRACT The cosmological principle, the combined assumptions of cosmological isotropy and homogeneity, underpins the standard model of big bang cosmology with which we interpret astronomical observations. A new test of isotropy over the redshift range 2 &lt; z &lt; 4 and across large angular scales on the sky is presented. We use the cosmological distribution of neutral hydrogen, as probed by the Ly α forest seen towards distant quasars. The Sloan Digital Sky Survey provides the largest data set of quasar spectra available to date. We use combined information from Data Releases 12 and 14 to select a sample of 142 661 quasars most suitable for this purpose. The scales covered by the data extend beyond post-inflation causality scales, thus probing initial conditions in the early Universe. We identify significant spatially correlated systematic effects that can emulate cosmological anisotropy. Once these systematics have been accounted for, the data are found to be consistent with isotropy, providing an important independent check on the standard model, consistent with results from cosmic microwave background data.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A10 ◽  
Author(s):  
F. Pacaud ◽  
M. Pierre ◽  
J.-B. Melin ◽  
C. Adami ◽  
A. E. Evrard ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Signal To Noise Ratio ◽  
Cosmological Parameters ◽  
Scaling Relations ◽  
High Signal ◽  
Selection Function ◽  
Redshift Distribution ◽  
Self Consistent ◽  
Consistent Manner ◽  
Current Mass

Context. We present an estimation of cosmological parameters with clusters of galaxies. Aims. We constrain the Ωm, σ8, and w parameters from a stand-alone sample of X-ray clusters detected in the 50 deg2 XMM-XXL survey with a well-defined selection function. Methods. We analyse the redshift distribution of a sample comprising 178 high signal-to-noise ratio clusters out to a redshift of unity. The cluster sample scaling relations are determined in a self-consistent manner. Results. In a lambda cold dark matter (ΛCDM) model, the cosmology favoured by the XXL clusters compares well with results derived from the Planck Sunyaev-Zel’dovich clusters for a totally different sample (mass/redshift range, selection biases, and scaling relations). However, with this preliminary sample and current mass calibration uncertainty, we find no inconsistency with the Planck CMB cosmology. If we relax the w parameter, the Planck CMB uncertainties increase by a factor of ~10 and become comparable with those from XXL clusters. Combining the two probes allows us to put constraints on Ωm = 0.316 ± 0.060, σ8 = 0.814 ± 0.054, and w = −1.02 ± 0.20. Conclusions. This first self-consistent cosmological analysis of a sample of serendipitous XMM clusters already provides interesting insights into the constraining power of the XXL survey. Subsequent analysis will use a larger sample extending to lower confidence detections and include additional observable information, potentially improving posterior uncertainties by roughly a factor of 3.

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