scholarly journals Can assembly bias explain the lensing amplitude of the BOSS CMASS sample in a Planck cosmology?

2020 ◽  
Vol 493 (4) ◽  
pp. 5551-5564
Author(s):  
Sihan Yuan ◽  
Daniel J Eisenstein ◽  
Alexie Leauthaud
Keyword(s):  
Cold Dark Matter ◽  
Cosmological Parameters ◽  
Bias Parameter ◽  
Projected Clustering ◽  
The Galaxy ◽  
Satellite Velocity ◽  
Galaxy Sample ◽  
Best Fitting ◽  
Galaxy Assembly ◽  
Halo Occupation Distribution

ABSTRACT In this paper, we investigate whether galaxy assembly bias can reconcile the 20–40 ${{\ \rm per\ cent}}$ disagreement between the observed galaxy projected clustering signal and the galaxy–galaxy lensing signal in the Baryon Oscillation Spectroscopic Survey CMASS galaxy sample. We use the suite of abacuscosmos lambda cold dark matter simulations at Planck best-fitting cosmology and two flexible implementations of extended halo occupation distribution (HOD) models that incorporate galaxy assembly bias to build forward models and produce joint fits of the observed galaxy clustering signal and the galaxy–galaxy lensing signal. We find that our models using the standard HODs without any assembly bias generalizations continue to show a 20–40 ${{\ \rm per\ cent}}$ overprediction of the observed galaxy–galaxy lensing signal. We find that our implementations of galaxy assembly bias do not reconcile the two measurements at Planck best-fitting cosmology. In fact, despite incorporating galaxy assembly bias, the satellite distribution parameter, and the satellite velocity bias parameter into our extended HOD model, our fits still strongly suggest a $\sim \! 34{{\ \rm per\ cent}}$ discrepancy between the observed projected clustering and galaxy–galaxy lensing measurements. It remains to be seen whether a combination of other galaxy assembly bias models, alternative cosmological parameters, or baryonic effects can explain the amplitude difference between the two signals.

scholarly journals Hemispherical variance anomaly and reionization optical depth

2020 ◽  
Vol 499 (3) ◽  
pp. 3563-3570
Author(s):  
Márcio O’Dwyer ◽  
Craig J Copi ◽  
Johanna M Nagy ◽  
C Barth Netterfield ◽  
John Ruhl ◽  
...  
Keyword(s):  
Optical Depth ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Signal To Noise Ratio ◽  
Cosmological Parameters ◽  
Temperature Data ◽  
Microwave Background ◽  
Parameter Uncertainties ◽  
Polarization Data ◽  
Best Fitting

ABSTRACT Cosmic microwave background (CMB) full-sky temperature data show a hemispherical asymmetry in power nearly aligned with the Ecliptic, with the Northern hemisphere displaying an anomalously low variance, while the Southern hemisphere appears consistent with expectations from the best-fitting theory, Lambda Cold Dark Matter (ΛCDM). The low signal-to-noise ratio in current polarization data prevents a similar comparison. Polarization realizations constrained by temperature data show that in ΛCDM the lack of variance is not expected to be present in polarization data. Therefore, a natural way of testing whether the temperature result is a fluke is to measure the variance of CMB polarization components. In anticipation of future CMB experiments that will allow for high-precision large-scale polarization measurements, we study how the variance of polarization depends on ΛCDM-parameter uncertainties by forecasting polarization maps with Planck’s Markov chain Monte Carlo chains. We show that polarization variance is sensitive to present uncertainties in cosmological parameters, mainly due to current poor constraints on the reionization optical depth τ, which drives variance at low multipoles. We demonstrate how the improvement in the τ measurement seen between Planck’s two latest data releases results in a tighter constraint on polarization variance expectations. Finally, we consider even smaller uncertainties on τ and how more precise measurements of τ can drive the expectation for polarization variance in a hemisphere close to that of the cosmic-variance-limited distribution.

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 The mass and galaxy distribution around SZ-selected clusters

2021 ◽  
Author(s):  
T Shin ◽  
B Jain ◽  
S Adhikari ◽  
E J Baxter ◽  
C Chang ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Theoretical Models ◽  
Weak Lensing ◽  
Mass Selection ◽  
Atacama Cosmology Telescope ◽  
Cluster Mass ◽  
Dark Energy Survey ◽  
Radial Profiles ◽  
The Galaxy ◽  
Galaxy Sample

Abstract We present measurements of the radial profiles of the mass and galaxy number density around Sunyaev-Zel’dovich (SZ)-selected clusters using both weak lensing and galaxy counts. The clusters are selected from the Atacama Cosmology Telescope Data Release 5 and the galaxies from the Dark Energy Survey Year 3 dataset. With signal-to-noise of 62 (45) for galaxy (weak lensing) profiles over scales of about 0.2 − 20h−1 Mpc, these are the highest precision measurements for SZ-selected clusters to date. Because SZ selection closely approximates mass selection, these measurements enable several tests of theoretical models of the mass and light distribution around clusters. Our main findings are: 1. The splashback feature is detected at a consistent location in both the mass and galaxy profiles and its location is consistent with predictions of cold dark matter N-body simulations. 2. The full mass profile is also consistent with the simulations. 3. The shapes of the galaxy and lensing profiles are remarkably similar for our sample over the entire range of scales, from well inside the cluster halo to the quasilinear regime. We measure the dependence of the profile shapes on the galaxy sample, redshift and cluster mass. We extend the Diemer & Kravtsov model for the cluster profiles to the linear regime using perturbation theory and show that it provides a good match to the measured profiles. We also compare the measured profiles to predictions of the standard halo model and simulations that include hydrodynamics. Applications of these results to cluster mass estimation, cosmology and astrophysics are discussed.

scholarly journals Cosmological Evidence Modelling: a new simulation-based approach to constrain cosmology on non-linear scales

2019 ◽  
Vol 490 (2) ◽  
pp. 1870-1878 ◽  
Author(s):  
Johannes U Lange ◽  
Frank C van den Bosch ◽  
Andrew R Zentner ◽  
Kuan Wang ◽  
Andrew P Hearin ◽  
...  
Keyword(s):  
Parameter Space ◽  
Cosmological Parameters ◽  
Computational Cost ◽  
Simulation Based ◽  
Non Linear ◽  
Bayesian Evidence ◽  
The Galaxy ◽  
Complex Models ◽  
Galaxy Halo ◽  
Galaxy Assembly

ABSTRACT Extracting accurate cosmological information from galaxy–galaxy and galaxy–matter correlation functions on non-linear scales (${\lesssim } 10 \, h^{-1}{\rm {Mpc}}$) requires cosmological simulations. Additionally, one has to marginalize over several nuisance parameters of the galaxy–halo connection. However, the computational cost of such simulations prohibits naive implementations of stochastic posterior sampling methods like Markov chain Monte Carlo (MCMC) that would require of order $\mathcal {O}(10^6)$ samples in cosmological parameter space. Several groups have proposed surrogate models as a solution: a so-called emulator is trained to reproduce observables for a limited number of realizations in parameter space. Afterwards, this emulator is used as a surrogate model in an MCMC analysis. Here, we demonstrate a different method called Cosmological Evidence Modelling (CEM). First, for each simulation, we calculate the Bayesian evidence marginalized over the galaxy–halo connection by repeatedly populating the simulation with galaxies. We show that this Bayesian evidence is directly related to the posterior probability of cosmological parameters. Finally, we build a physically motivated model for how the evidence depends on cosmological parameters as sampled by the simulations. We demonstrate the feasibility of CEM by using simulations from the Aemulus simulation suite and forecasting cosmological constraints from BOSS CMASS measurements of redshift-space distortions. Our analysis includes exploration of how galaxy assembly bias affects cosmological inference. Overall, CEM has several potential advantages over the more common approach of emulating summary statistics, including the ability to easily marginalize over highly complex models of the galaxy–halo connection and greater accuracy, thereby reducing the number of simulations required.

scholarly journals The Atacama Cosmology Telescope: a CMB lensing mass map over 2100 square degrees of sky and its cross-correlation with BOSS-CMASS galaxies

2020 ◽  
Vol 500 (2) ◽  
pp. 2250-2263
Author(s):  
Omar Darwish ◽  
Mathew S Madhavacheril ◽  
Blake D Sherwin ◽  
Simone Aiola ◽  
Nicholas Battaglia ◽  
...  
Keyword(s):  
Cold Dark Matter ◽  
Cross Correlation ◽  
Signal To Noise Ratio ◽  
Microwave Background ◽  
Atacama Cosmology Telescope ◽  
Infrared Background ◽  
Galaxy Sample ◽  
Best Fitting ◽  
Galaxy Bias ◽  
Using Data

ABSTRACT We construct cosmic microwave background lensing mass maps using data from the 2014 and 2015 seasons of observations with the Atacama Cosmology Telescope (ACT). These maps cover 2100 square degrees of sky and overlap with a wide variety of optical surveys. The maps are signal dominated on large scales and have fidelity such that their correlation with the cosmic infrared background is clearly visible by eye. We also create lensing maps with thermal Sunyaev−Zel’dovich contamination removed using a novel cleaning procedure that only slightly degrades the lensing signal-to-noise ratio. The cross-spectrum between the cleaned lensing map and the BOSS CMASS galaxy sample is detected at 10σ significance, with an amplitude of A = 1.02 ± 0.10 relative to the Planck best-fitting Lambda cold dark matter cosmological model with fiducial linear galaxy bias. Our measurement lays the foundation for lensing cross-correlation science with current ACT data and beyond.

scholarly journals Multitracer extension of the halo model: probing quenching and conformity in eBOSS

2020 ◽  
Vol 497 (1) ◽  
pp. 581-595 ◽  
Author(s):  
Shadab Alam ◽  
John A Peacock ◽  
Katarina Kraljic ◽  
Ashley J Ross ◽  
Johan Comparat
Keyword(s):  
Statistical Significance ◽  
Low Density ◽  
Galaxy Distribution ◽  
Upper Limits ◽  
Quenching Efficiency ◽  
The Galaxy ◽  
Best Fitting ◽  
The Mean ◽  
Halo Masses ◽  
Halo Occupation Distribution

ABSTRACT We develop a new Multitracer Halo Occupation Distribution (MTHOD) framework for the galaxy distribution and apply it to the extended Baryon Oscillation Spectroscopic Survey (eBOSS) final data between z = 0.7 − 1.1. We obtain a best fitting MTHOD  for each tracer and describe the host halo properties of these galaxies. The mean halo masses for LRGs, ELGs, and QSOs are found to be $1.9 \times 10^{13} \, h^{-1}M_\odot$, $1.1 \times 10^{12} \, h^{-1}M_\odot$, and $5 \times 10^{12} \, h^{-1}M_\odot$ respectively in the eBOSS data. We use the MTHOD  framework to create mock galaxy catalogues and predict auto- and cross-correlation functions for all the tracers. Comparing these results with data, we investigate galactic conformity, the phenomenon whereby the properties of neighbouring galaxies are mutually correlated in a manner that is not captured by the basic halo model. We detect 1-halo conformity at more than 3σ statistical significance, while obtaining upper limits on 2-halo conformity. We also look at the environmental dependence of the galaxy quenching efficiency and find that halo mass driven quenching successfully explains the behaviour in high density regions, but it fails to describe the quenching efficiency in low density regions. In particular, we show that the quenching efficiency in low density filaments is higher in the observed data, as compared to the prediction of the MTHOD with halo mass driven quenching. The mock galaxy catalogue constructed in this paper is publicly available on this website1.

scholarly journals A Robust Technique for Estimating Cosmological Parameters

2005 ◽  
Vol 201 ◽  
pp. 467-468
Author(s):  
Martin A. Hendry ◽  
Stéphane Rauzy
Keyword(s):  
Luminosity Function ◽  
Spatial Clustering ◽  
Cosmological Parameters ◽  
Bias Parameter ◽  
Galaxy Surveys ◽  
The Galaxy ◽  
Distance Data ◽  
Galaxy Luminosity Function

We present a new ROBUST technique for extracting information from galaxy surveys which allows determination of cosmological parameters free of almost any model assumptions concerning the galaxy luminosity function and spatial clustering. We illustrate ROBUST by estimating H0 and the linear bias parameter, β, from recent redshift-distance data.

scholarly journals The Completed SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: N-body Mock Challenge for Galaxy Clustering Measurements

2020 ◽  
Author(s):  
Graziano Rossi ◽  
Peter D Choi ◽  
Jeongin Moon ◽  
Julian E Bautista ◽  
Hector Gil-Marín ◽  
...  
Keyword(s):  
Final Analysis ◽  
Acoustic Oscillation ◽  
Luminous Red Galaxies ◽  
The Galaxy ◽  
Galaxy Sample ◽  
Space Distortion ◽  
Galaxy Halo ◽  
Red Galaxies ◽  
Shape Clustering ◽  
Halo Occupation Distribution

Abstract We develop a series of N-body data challenges, functional to the final analysis of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16) galaxy sample. The challenges are primarily based on high-fidelity catalogs constructed from the Outer Rim simulation – a large box size realization (3h−1Gpc) characterized by an unprecedented combination of volume and mass resolution, down to 1.85 · 109h−1M⊙. We generate synthetic galaxy mocks by populating Outer Rim halos with a variety of halo occupation distribution (HOD) schemes of increasing complexity, spanning different redshift intervals. We then assess the performance of three complementary redshift space distortion (RSD) models in configuration and Fourier space, adopted for the analysis of the complete DR16 eBOSS sample of Luminous Red Galaxies (LRGs). We find all the methods mutually consistent, with comparable systematic errors on the Alcock-Paczynski parameters and the growth of structure, and robust to different HOD prescriptions – thus validating the robustness of the models and the pipelines used for the baryon acoustic oscillation (BAO) and full shape clustering analysis. In particular, all the techniques are able to recover α∥ and α⊥ to within $0.9\%$, and fσ8 to within $1.5\%$. As a by-product of our work, we are also able to gain interesting insights on the galaxy-halo connection. Our study is relevant for the final eBOSS DR16 ‘consensus cosmology’, as the systematic error budget is informed by testing the results of analyses against these high-resolution mocks. In addition, it is also useful for future large-volume surveys, since similar mock-making techniques and systematic corrections can be readily extended to model for instance the Dark Energy Spectroscopic Instrument (DESI) galaxy sample.

scholarly journals Viability tests of f(R)-gravity models with Supernovae Type 1A data

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
R. T. Hough ◽  
A. Abebe ◽  
S. E. S. Ferreira
Keyword(s):  
Density Distribution ◽  
Gravity Model ◽  
Cold Dark Matter ◽  
Likelihood Function ◽  
Cosmological Parameters ◽  
Gravity Models ◽  
Light Curve Analysis ◽  
Starobinsky Model ◽  
Mcmc Simulation ◽  
Best Fitting

Abstract In this work, we will be testing four different general f(R)-gravity models, two of which are the more realistic models (namely the Starobinsky and the Hu–Sawicki models), to determine if they are viable alternative models to pursue a more vigorous constraining test upon them. For the testing of these models, we use 359 low- and intermediate-redshift Supernovae Type 1A data obtained from the SDSS-II/SNLS2 Joint Light-curve Analysis (JLA). We develop a Markov Chain Monte Carlo (MCMC) simulation to find a best-fitting function within reasonable ranges for each f(R)-gravity model, as well as for the Lambda Cold Dark Matter ($$\varLambda $$ΛCDM) model. For simplicity, we assume a flat universe with a negligible radiation density distribution. Therefore, the only difference between the accepted $$\varLambda $$ΛCDM model and the f(R)-gravity models will be the dark energy term and the arbitrary free parameters. By doing a statistical analysis and using the $$\varLambda $$ΛCDM model as our “true model”, we can obtain an indication whether or not a certain f(R)-gravity model shows promise and requires a more in-depth view in future studies. In our results, we found that the Starobinsky model obtained a larger likelihood function value than the $$\varLambda $$ΛCDM model, while still obtaining the cosmological parameters to be $$\varOmega _{m} = 0.268^{+0.027}_{-0.024}$$Ωm=0.268-0.024+0.027 for the matter density distribution and $${\bar{h}} = 0.690^{+0.005}_{-0.005}$$h¯=0.690-0.005+0.005 for the Hubble uncertainty parameter. We also found a reduced Starobinsky model that are able to explain the data, as well as being statistically significant.

scholarly journals How to optimally constrain galaxy assembly bias: supplement projected correlation functions with count-in-cells statistics

2019 ◽  
Vol 488 (3) ◽  
pp. 3541-3567 ◽  
Author(s):  
Kuan Wang ◽  
Yao-Yuan Mao ◽  
Andrew R Zentner ◽  
Frank C van den Bosch ◽  
Johannes U Lange ◽  
...  
Keyword(s):  
Survey Data ◽  
Frequent Use ◽  
The Galaxy ◽  
Point Correlation ◽  
Point Correlation Function ◽  
Redshift Survey ◽  
Galaxy Halo ◽  
Statistical Connection ◽  
Galaxy Assembly ◽  
Halo Occupation Distribution

ABSTRACT Most models for the statistical connection between galaxies and their haloes ignore the possibility that galaxy properties may be correlated with halo properties other than halo mass, a phenomenon known as galaxy assembly bias. And yet, it is known that such correlations can lead to systematic errors in the interpretation of survey data that are analysed using traditional halo occupation models. At present, the degree to which galaxy assembly bias may be present in the real Universe, and the best strategies for constraining it remain uncertain. We study the ability of several observables to constrain galaxy assembly bias from redshift survey data using the decorated halo occupation distribution (dHOD), an empirical model of the galaxy–halo connection that incorporates assembly bias. We cover an expansive set of observables, including the projected two-point correlation function wp(rp), the galaxy–galaxy lensing signal ΔΣ(rp), the void probability function VPF(r), the distributions of counts-in-cylinders P(NCIC), and counts-in-annuli P(NCIA), and the distribution of the ratio of counts in cylinders of different sizes P(N2/N5). We find that despite the frequent use of the combination wp(rp) + ΔΣ(rp) in interpreting galaxy data, the count statistics, P(NCIC) and P(NCIA), are generally more efficient in constraining galaxy assembly bias when combined with wp(rp). Constraints based upon wp(rp) and ΔΣ(rp) share common degeneracy directions in the parameter space, while combinations of wp(rp) with the count statistics are more complementary. Therefore, we strongly suggest that count statistics should be used to complement the canonical observables in future studies of the galaxy–halo connection.

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