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 Characterizing the abundance, properties, and kinematics of the cool circumgalactic medium of galaxies in absorption with SDSS DR16

2021 ◽  
Vol 504 (1) ◽  
pp. 65-88
Author(s):  
Abhijeet Anand ◽  
Dylan Nelson ◽  
Guinevere Kauffmann
Keyword(s):  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
Gas Absorption ◽  
Dark Matter Halo ◽  
Star Forming ◽  
Sky Survey ◽  
Optical Continuum ◽  
Circumgalactic Medium ◽  
Emission Line Galaxies ◽  
Red Galaxies

ABSTRACT In order to study the circumgalactic medium (CGM) of galaxies we develop an automated pipeline to estimate the optical continuum of quasars and detect intervening metal absorption line systems with a matched kernel convolution technique and adaptive S/N criteria. We process ∼ one million quasars in the latest Data Release 16 (DR16) of the Sloan Digital Sky Survey (SDSS) and compile a large sample of ∼ 160 000 Mg ii absorbers, together with ∼ 70 000 Fe ii systems, in the redshift range 0.35 < zabs < 2.3. Combining these with the SDSS DR16 spectroscopy of ∼1.1 million luminous red galaxies (LRGs) and ∼200 000 emission line galaxies (ELGs), we investigate the nature of cold gas absorption at 0.5 < z < 1. These large samples allow us to characterize the scale dependence of Mg ii with greater accuracy than in previous work. We find that there is a strong enhancement of Mg ii absorption within ∼50 kpc of ELGs, and the covering fraction within 0.5rvir of ELGs is 2–5 times higher than for LRGs. Beyond 50 kpc, there is a sharp decline in Mg ii for both kinds of galaxies, indicating a transition to the regime where the CGM is tightly linked with the dark matter halo. The Mg ii-covering fraction correlates strongly with stellar mass for LRGs, but weakly for ELGs, where covering fractions increase with star formation rate. Our analysis implies that cool circumgalactic gas has a different physical origin for star-forming versus quiescent galaxies.

scholarly journals Cosmology with galaxy–galaxy lensing on non-perturbative scales: emulation method and application to BOSS LOWZ

2019 ◽  
Vol 492 (2) ◽  
pp. 2872-2896 ◽  
Author(s):  
Benjamin D Wibking ◽  
David H Weinberg ◽  
Andrés N Salcedo ◽  
Hao-Yi Wu ◽  
Sukhdeep Singh ◽  
...  
Keyword(s):  
Cosmological Parameters ◽  
Linear Structure ◽  
Sloan Digital Sky Survey ◽  
Projected Clustering ◽  
True Value ◽  
Data Release ◽  
Non Linear ◽  
Galaxy Sample ◽  
Galaxy Bias ◽  
Red Galaxies

ABSTRACT We describe our non-linear emulation (i.e. interpolation) framework that combines the halo occupation distribution (HOD) galaxy bias model with N-body simulations of non-linear structure formation, designed to accurately predict the projected clustering and galaxy–galaxy lensing signals from luminous red galaxies in the redshift range 0.16 < z < 0.36 on comoving scales 0.6 < rp < 30 $h^{-1} \, \text{Mpc}$. The interpolation accuracy is ≲ 1–2 per cent across the entire physically plausible range of parameters for all scales considered. We correctly recover the true value of the cosmological parameter S8 = (σ8/0.8228)(Ωm/0.3107)0.6 from mock measurements produced via subhalo abundance matching (SHAM)-based light-cones designed to approximately match the properties of the SDSS LOWZ galaxy sample. Applying our model to Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 14 (DR14) LOWZ galaxy clustering and galaxy-shear cross-correlation measurements made with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) imaging, we perform a prototype cosmological analysis marginalizing over wCDM cosmological parameters and galaxy HOD parameters. We obtain a 4.4 per cent measurement of S8 = 0.847 ± 0.037, in 3.5σ tension with the Planck cosmological results of 1.00 ± 0.02. We discuss the possibility of underestimated systematic uncertainties or astrophysical effects that could explain this discrepancy.

scholarly journals Testing the reliability of fast methods for weak lensing simulations: wl-moka on pinocchio

2020 ◽  
Vol 496 (2) ◽  
pp. 1307-1324
Author(s):  
Carlo Giocoli ◽  
Pierluigi Monaco ◽  
Lauro Moscardini ◽  
Tiago Castro ◽  
Massimo Meneghetti ◽  
...  
Keyword(s):  
Large Scale ◽  
Initial Conditions ◽  
Mass Density ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Mass Function ◽  
Parametric Models ◽  
Weak Lensing ◽  
Approximate Methods ◽  
Percent Accuracy

ABSTRACT The generation of simulated convergence maps is of key importance in fully exploiting weak lensing by large-scale structure (LSS) from which cosmological parameters can be derived. In this paper, we present an extension of the pinocchio code that produces catalogues of dark matter haloes so that it is capable of simulating weak lensing by Modify LSS into Large Scale Structures (LSS). Like wl-moka, the method starts with a random realization of cosmological initial conditions, creates a halo catalogue and projects it on to the past light-cone, and paints in haloes assuming parametric models for the mass density distribution within them. Large-scale modes that are not accounted for by the haloes are constructed using linear theory. We discuss the systematic errors affecting the convergence power spectra when Lagrangian perturbation theory at increasing order is used to displace the haloes within pinocchio, and how they depend on the grid resolution. Our approximate method is shown to be very fast when compared to full ray-tracing simulations from an N-body run and able to recover the weak lensing signal, at different redshifts, with a few percent accuracy. It also allows for quickly constructing weak lensing covariance matrices, complementing pinocchio’s ability of generating the cluster mass function and galaxy clustering covariances and thus paving the way for calculating cross-covariances between the different probes. This work advances these approximate methods as tools for simulating and analysing survey data for cosmological purposes.

scholarly journals Improving galaxy clustering measurements with deep learning: analysis of the DECaLS DR7 data

2020 ◽  
Vol 495 (2) ◽  
pp. 1613-1640 ◽  
Author(s):  
Mehdi Rezaie ◽  
Hee-Jong Seo ◽  
Ashley J Ross ◽  
Razvan C Bunescu
Keyword(s):  
Dark Energy ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Density Field ◽  
Data Sets ◽  
Galaxy Surveys ◽  
The Neural Network ◽  
Systematic Effects ◽  
Robust Measurements ◽  
Emission Line Galaxies

ABSTRACT Robust measurements of cosmological parameters from galaxy surveys rely on our understanding of systematic effects that impact the observed galaxy density field. In this paper, we present, validate, and implement the idea of adopting the systematics mitigation method of artificial neural networks for modelling the relationship between the target galaxy density field and various observational realities including but not limited to Galactic extinction, seeing, and stellar density. Our method by construction allows a wide class of models and alleviates overtraining by performing k-fold cross-validation and dimensionality reduction via backward feature elimination. By permuting the choice of the training, validation, and test sets, we construct a selection mask for the entire footprint. We apply our method on the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Emission Line Galaxies (ELGs) selection from the Dark Energy Camera Legacy Survey (DECaLS) Data Release 7 and show that the spurious large-scale contamination due to imaging systematics can be significantly reduced by up-weighting the observed galaxy density using the selection mask from the neural network and that our method is more effective than the conventional linear and quadratic polynomial functions. We perform extensive analyses on simulated mock data sets with and without systematic effects. Our analyses indicate that our methodology is more robust to overfitting compared to the conventional methods. This method can be utilized in the catalogue generation of future spectroscopic galaxy surveys such as eBOSS and Dark Energy Spectroscopic Instrument (DESI) to better mitigate observational systematics.

scholarly journals High-redshift cosmology with oxygen lines from Hα surveys

2020 ◽  
Vol 495 (1) ◽  
pp. 1340-1348
Author(s):  
José Fonseca ◽  
Stefano Camera
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Galaxy Surveys ◽  
Redshift Galaxy ◽  
Scientific Potential ◽  
Galaxy Sample ◽  
Emission Line Galaxies ◽  
Infrared Frequencies

ABSTRACT A new generation of cosmological experiments will spectroscopically detect the Hα line from emission-line galaxies at optical/near-infrared frequencies. Other emission lines will also be present, which may come from the same Hα sample or constitute a new galaxy sample altogether. Our goal is to assess the value, for cosmological investigation, of galaxies at z ≳ 2 present in Hα galaxy surveys and identifiable by the highly redshifted ultraviolet and optical lines – namely the O ii line and the O iii doublet in combination with the Hβ line. We use state-of-the-art luminosity functions to estimate the number density of O iii + Hβ and O ii ELGs. We study the constraining power of these high-redshift galaxy samples on cosmological parameters such as the baryon acoustic oscillation (BAO) amplitude, H(z), DA(z), fσ8(z), and bσ8(z) for different survey designs. We present a strong science case for extracting the O iii + Hβ sample, which we consider as an independent probe of the Universe in the redshift range 2−3. Moreover, we show that the O ii sample can be used to measure the BAO and growth of structure above z = 3; albeit it may be shot-noise dominated, it will none the less provide valuable tomographic information. We discuss the scientific potential of a sample of galaxies, which, so far, has been mainly considered as a contaminant in Hα galaxy surveys. Our findings indicate that planed Hα surveys should include the extraction of these oxygen-line samples in their pipeline, to enhance their scientific impact on cosmology.

scholarly journals The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: measurement of the BAO and growth rate of structure of the emission line galaxy sample from the anisotropic power spectrum between redshift 0.6 and 1.1

2020 ◽  
Author(s):  
Arnaud de Mattia ◽  
Vanina Ruhlmann-Kleider ◽  
Anand Raichoor ◽  
Ashley J Ross ◽  
Amélie Tamone ◽  
...  
Keyword(s):  
Growth Rate ◽  
Power Spectrum ◽  
Emission Line ◽  
Large Scale ◽  
Sloan Digital Sky Survey ◽  
Full Data ◽  
Data Set ◽  
Weak Preference ◽  
Galaxy Sample ◽  
Emission Line Galaxies

Abstract We analyse the large-scale clustering in Fourier space of emission line galaxies (ELG) from the Data Release 16 of the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey. The ELG sample contains 173,736 galaxies covering 1,170 square degrees in the redshift range 0.6 < z < 1.1. We perform a BAO measurement from the post-reconstruction power spectrum monopole, and study redshift space distortions (RSD) in the first three even multipoles. Photometric variations yield fluctuations of both the angular and radial survey selection functions. Those are directly inferred from data, imposing integral constraints which we model consistently. The full data set has only a weak preference for a BAO feature (1.4σ). At the effective redshift zeff = 0.845 we measure $D_{\rm V}(z_{\rm eff})/r_{\rm drag} = 18.33_{-0.62}^{+0.57}$, with DV the volume-averaged distance and rdrag the comoving sound horizon at the drag epoch. In combination with the RSD measurement, at zeff = 0.85 we find $f\sigma _8(z_{\rm eff}) = 0.289_{-0.096}^{+0.085}$, with f the growth rate of structure and σ8 the normalisation of the linear power spectrum, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 20.0_{-2.2}^{+2.4}$ and DM(zeff)/rdrag = 19.17 ± 0.99 with DH and DM the Hubble and comoving angular distances, respectively. These results are in agreement with those obtained in configuration space, thus allowing a consensus measurement of fσ8(zeff) = 0.315 ± 0.095, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 19.6_{-2.1}^{+2.2}$ and DM(zeff)/rdrag = 19.5 ± 1.0. This measurement is consistent with a flat ΛCDM model with Planck parameters.

scholarly journals Iterative removal of redshift-space distortions from galaxy clustering

2020 ◽  
Vol 497 (3) ◽  
pp. 3451-3471
Author(s):  
Yuchan Wang ◽  
Baojiu Li ◽  
Marius Cautun
Keyword(s):  
Large Scale ◽  
Initial Density ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Real Space ◽  
Density Field ◽  
Theoretical Modelling ◽  
Galaxy Clustering ◽  
Reconstruction Process ◽  
The Real

ABSTRACT Observations of galaxy clustering are made in redshift space, which results in distortions to the underlying isotropic distribution of galaxies. These redshift-space distortions (RSDs) not only degrade important features of the matter density field, such as the baryonic acoustic oscillation (BAO) peaks, but also pose challenges for the theoretical modelling of observational probes. Here, we introduce an iterative non-linear reconstruction algorithm to remove RSD effects from galaxy clustering measurements, and assess its performance by using mock galaxy catalogues. The new method is found to be able to recover the real-space galaxy correlation function with an accuracy of $\sim \!1{{\ \rm per\ cent}}$, and restore the quadrupole accurately to 0, on scales $s\gtrsim 20\,h^{-1}\, {\rm Mpc}$. It also leads to an improvement in the reconstruction of the initial density field, which could help to accurately locate the BAO peaks. An ‘internal calibration’ scheme is proposed to determine the values of cosmological parameters, as a part of the reconstruction process, and possibilities to break parameter degeneracies are discussed. RSD reconstruction can offer a potential way to simultaneously extract the cosmological parameters, initial density field, real-space galaxy positions, and large-scale peculiar velocity field (of the real Universe), making it an alternative to standard perturbative approaches in galaxy clustering analysis, bypassing the need for RSD modelling.

scholarly journals Planck 2018 results

2020 ◽  
Vol 641 ◽  
pp. A8 ◽  
Author(s):  
◽  
N. Aghanim ◽  
Y. Akrami ◽  
M. Ashdown ◽  
J. Aumont ◽  
...  
Keyword(s):  
Power Spectrum ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Acoustic Oscillation ◽  
Minimum Variance ◽  
Baryon Density ◽  
Small Scale ◽  
Individual Parameter ◽  
Parameter Constraints

We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5σ to 9σ. Combined with temperature, lensing is detected at 40σ. We present an extensive set of tests of the robustness of the lensing-potential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles 8 ≤ L ≤ 400 (extending the range to lower L compared to 2015), which we use to constrain cosmological parameters. We find good consistency between lensing constraints and the results from the Planck CMB power spectra within the ΛCDM model. Combined with baryon density and other weak priors, the lensing analysis alone constrains σ8Ωm0.25 = 0.589 ± 0.020 (1σ errors). Also combining with baryon acoustic oscillation data, we find tight individual parameter constraints, σ8 = 0.811 ± 0.019, H0 = 67.9−1.3+1.2 km s−1 Mpc−1, and Ωm = 0.303−0.018+0.016. Combining with Planck CMB power spectrum data, we measure σ8 to better than 1% precision, finding σ8 = 0.811 ± 0.006. CMB lensing reconstruction data are complementary to galaxy lensing data at lower redshift, having a different degeneracy direction in σ8 − Ωm space; we find consistency with the lensing results from the Dark Energy Survey, and give combined lensing-only parameter constraints that are tighter than joint results using galaxy clustering. Using the Planck cosmic infrared background (CIB) maps as an additional tracer of high-redshift matter, we make a combined Planck-only estimate of the lensing potential over 60% of the sky with considerably more small-scale signal. We additionally demonstrate delensing of the Planck power spectra using the joint and individual lensing potential estimates, detecting a maximum removal of 40% of the lensing-induced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance.

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.

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