scholarly journals Towards a self-consistent analysis of the anisotropic galaxy two- and three-point correlation functions on large scales: application to mock galaxy catalogues

2020 ◽  
Author(s):  
Naonori S Sugiyama ◽  
Shun Saito ◽  
Florian Beutler ◽  
Hee-Jong Seo
Keyword(s):  
Correlation Functions ◽  
Hubble Parameter ◽  
Theoretical Models ◽  
Practical Method ◽  
Acoustic Oscillation ◽  
Nonlinear Damping ◽  
Joint Analysis ◽  
Angular Diameter Distance ◽  
Point Correlation ◽  
Parameter Constraints

Abstract We establish a practical method for the joint analysis of anisotropic galaxy two- and three-point correlation functions (2PCF and 3PCF) on the basis of the decomposition formalism of the 3PCF using tri-polar spherical harmonics. We perform such an analysis with MultiDark Patchy mock catalogues to demonstrate and understand the benefit of the anisotropic 3PCF. We focus on scales above 80 h−1 Mpc, and use information from the shape and the baryon acoustic oscillation (BAO) signals of the 2PCF and 3PCF. We also apply density field reconstruction to increase the signal-noise ratio of BAO in the 2PCF measurement, but not in the 3PCF measurement. In particular, we study in detail the constraints on the angular diameter distance and the Hubble parameter. We build a model of the bispectrum or 3PCF that includes the nonlinear damping of the BAO signal in redshift space. We carefully account for various uncertainties in our analysis including theoretical models of the 3PCF, window function corrections, biases in estimated parameters from the fiducial values, the number of mock realizations to estimate the covariance matrix, and bin size. The joint analysis of the 2PCF and 3PCF monopole and quadrupole components shows a $30\%$ and $20\%$ improvement in Hubble parameter constraints before and after reconstruction of the 2PCF measurements, respectively, compared to the 2PCF analysis alone. This study clearly shows that the anisotropic 3PCF increases cosmological information from galaxy surveys and encourages further development of the modeling of the 3PCF on smaller scales than we consider.

scholarly journals Constraints on cosmological parameters from gamma-ray burst peak photon energy and bolometric fluence measurements and other data

2020 ◽  
Vol 499 (1) ◽  
pp. 391-403 ◽  
Author(s):  
Narayan Khadka ◽  
Bharat Ratra
Keyword(s):  
Photon Energy ◽  
Hubble Parameter ◽  
Gamma Ray ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Cosmological Models ◽  
Gamma Ray Bursts ◽  
Joint Analysis ◽  
Baryon Acoustic Oscillation ◽  
Parameter Constraints

ABSTRACT We use measurements of the peak photon energy and bolometric fluence of 119 gamma-ray bursts (GRBs) extending over the redshift range of 0.3399 ≤ z ≤ 8.2 to simultaneously determine cosmological and Amati relation parameters in six different cosmological models. The resulting Amati relation parameters are almost identical in all six cosmological models, thus validating the use of the Amati relation in standardizing these GRBs. The GRB data cosmological parameter constraints are consistent with, but significantly less restrictive than, those obtained from a joint analysis of baryon acoustic oscillation and Hubble parameter measurements.

scholarly journals Using quasar X-ray and UV flux measurements to constrain cosmological model parameters

2020 ◽  
Vol 497 (1) ◽  
pp. 263-278 ◽  
Author(s):  
Narayan Khadka ◽  
Bharat Ratra
Keyword(s):  
Cosmological Parameters ◽  
Hubble Constant ◽  
Acoustic Oscillation ◽  
Joint Analysis ◽  
Model Parameters ◽  
Density Parameter ◽  
Current Standard ◽  
X Ray ◽  
Flux Measurements ◽  
Parameter Constraints

ABSTRACT Risaliti and Lusso have compiled X-ray and UV flux measurements of 1598 quasars (QSOs) in the redshift range 0.036 ≤ z ≤ 5.1003, part of which, z ∼ 2.4 − 5.1, is largely cosmologically unprobed. In this paper we use these QSO measurements, alone and in conjunction with baryon acoustic oscillation (BAO) and Hubble parameter [H(z)] measurements, to constrain cosmological parameters in six different cosmological models, each with two different Hubble constant priors. In most of these models, given the larger uncertainties, the QSO cosmological parameter constraints are mostly consistent with those from the BAO + H(z) data. A somewhat significant exception is the non-relativistic matter density parameter Ωm0 where QSO data favour Ωm0 ∼ 0.5 − 0.6 in most models. As a result, in joint analyses of QSO data with H(z) + BAO data the 1D Ωm0 distributions shift slightly towards larger values. A joint analysis of the QSO + BAO + H(z) data is consistent with the current standard model, spatially-flat ΛCDM, but mildly favours closed spatial hypersurfaces and dynamical dark energy. Since the higher Ωm0 values favoured by QSO data appear to be associated with the z ∼ 2 − 5 part of these data, and conflict somewhat with strong indications for Ωm0 ∼ 0.3 from most z < 2.5 data as well as from the cosmic microwave background anisotropy data at z ∼ 1100, in most models, the larger QSO data Ωm0 is possibly more indicative of an issue with the z ∼ 2 − 5 QSO data than of an inadequacy of the standard flat ΛCDM model.

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 A clustering-based self-calibration of the richness-to-mass relation of CAMIRA galaxy clusters out to z ≈ 1.1 in the Hyper Suprime-Cam survey

2020 ◽  
Vol 498 (2) ◽  
pp. 2030-2053 ◽  
Author(s):  
I-Non Chiu ◽  
Teppei Okumura ◽  
Masamune Oguri ◽  
Aniket Agrawal ◽  
Keiichi Umetsu ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Autocorrelation Function ◽  
Correlation Functions ◽  
Joint Analysis ◽  
Mass Relation ◽  
Large Set ◽  
Self Calibration ◽  
Two Samples ◽  
The Impact ◽  
Parameter Constraints

ABSTRACT We perform a self-calibration of the richness-to-mass (N–M) relation of CAMIRA galaxy clusters with richness N ≥ 15 at redshift 0.2 ≤ z < 1.1 by modelling redshift-space two-point correlation functions. These correlation functions are the autocorrelation function ξcc of CAMIRA clusters, the autocorrelation function ξgg of the CMASS galaxies spectroscopically observed in the Baryon Oscillation Spectroscopic Survey, and the cross-correlation function ξcg between these two samples. We focus on constraining the normalization AN of the N–M relation with a forward-modelling approach, carefully accounting for the redshift-space distortion, the Finger-of-God effect, and the uncertainty in photometric redshifts of CAMIRA clusters. The modelling also takes into account the projection effect on the halo bias of CAMIRA clusters. The parameter constraints are shown to be unbiased according to validation tests using a large set of mock catalogues constructed from N-body simulations. At the pivotal mass $M_{500}=10^{14}\, h^{-1}\, \mathrm{M}_{\odot }$ and the pivotal redshift zpiv = 0.6, the resulting normalization AN is constrained as $13.8^{+5.8}_{-4.2}$, $13.2^{+3.4}_{-2.7}$, and $11.9^{+3.0}_{-1.9}$ by modelling ξcc, ξcc + ξcg, and ξcc + ξcg + ξgg, with average uncertainties at levels of 36, 23, and $21{{\ \rm per\ cent}}$, respectively. We find that the resulting AN is statistically consistent with those independently obtained from weak-lensing magnification and from a joint analysis of shear and cluster abundance, with a preference for a lower value at a level of ≲ 1.9σ. This implies that the absolute mass scale of CAMIRA clusters inferred from clustering is mildly higher than those from the independent methods. We discuss the impact of the selection bias introduced by the cluster finding algorithm, which is suggested to be a subdominant factor in this work.

scholarly journals Non-Gaussianity in the weak lensing correlation function likelihood – implications for cosmological parameter biases

2020 ◽  
Vol 499 (2) ◽  
pp. 2977-2993
Author(s):  
Chien-Hao Lin ◽  
Joachim Harnois-Déraps ◽  
Tim Eifler ◽  
Taylor Pospisil ◽  
Rachel Mandelbaum ◽  
...  
Keyword(s):  
Correlation Functions ◽  
Principal Component ◽  
Cosmological Parameter ◽  
Weak Lensing ◽  
Likelihood Model ◽  
Point Correlation ◽  
Parametric Functions ◽  
Non Gaussian ◽  
Parameter Constraints ◽  
Skewness And Kurtosis

ABSTRACT We study the significance of non-Gaussianity in the likelihood of weak lensing shear two-point correlation functions, detecting significantly non-zero skewness and kurtosis in 1D marginal distributions of shear two-point correlation functions in simulated weak lensing data. We examine the implications in the context of future surveys, in particular LSST, with derivations of how the non-Gaussianity scales with survey area. We show that there is no significant bias in 1D posteriors of Ωm and σ8 due to the non-Gaussian likelihood distributions of shear correlations functions using the mock data (100 deg2). We also present a systematic approach to constructing approximate multivariate likelihoods with 1D parametric functions by assuming independence or more flexible non-parametric multivariate methods after decorrelating the data points using principal component analysis (PCA). While the use of PCA does not modify the non-Gaussianity of the multivariate likelihood, we find empirically that the 1D marginal sampling distributions of the PCA components exhibit less skewness and kurtosis than the original shear correlation functions. Modelling the likelihood with marginal parametric functions based on the assumption of independence between PCA components thus gives a lower limit for the biases. We further demonstrate that the difference in cosmological parameter constraints between the multivariate Gaussian likelihood model and more complex non-Gaussian likelihood models would be even smaller for an LSST-like survey. In addition, the PCA approach automatically serves as a data compression method, enabling the retention of the majority of the cosmological information while reducing the dimensionality of the data vector by a factor of ∼5.

scholarly journals Clustering of dark halos on the lightcone

2003 ◽  
Vol 208 ◽  
pp. 467-468
Author(s):  
Naoki Yoshida ◽  
Takashi Hamana ◽  
Yasushi Suto ◽  
August Evrard
Keyword(s):  
Dark Matter ◽  
Phenomenological Model ◽  
Correlation Functions ◽  
Light Cone ◽  
Theoretical Models ◽  
Dark Matter Halos ◽  
Model Predictions ◽  
Astrophysical Objects ◽  
Point Correlation ◽  
Good Agreement

We present a phenomenological model to predict the clustering of dark matter halos on the light-cone. The model is constructed by combining several existing theoretical models. We test our model against the Hubble Volume N-body simulation and examine its validity. A good agreement is found in two-point correlation functions of dark matter halos between our model predictions and measurements from the simulation. The model is quite general and thus can be applied to a wider range of astrophysical objects, such as galaxies and quasars.

scholarly journals THE FREE FIELD REPRESENTATION OF SU(3) CONFORMAL FIELD THEORY

1993 ◽  
Vol 08 (23) ◽  
pp. 4031-4053
Author(s):  
HOVIK D. TOOMASSIAN
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Correlation Functions ◽  
Free Field ◽  
Field Representation ◽  
Conformal Field ◽  
Point Correlation

The structure of the free field representation and some four-point correlation functions of the SU(3) conformal field theory are considered.

scholarly journals From correlation functions to event shapes in QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
D. Chicherin ◽  
J. M. Henn ◽  
E. Sokatchev ◽  
K. Yan
Keyword(s):  
Correlation Function ◽  
Correlation Functions ◽  
Event Shape ◽  
Proof Of Concept ◽  
Yang Mills ◽  
Point Correlation ◽  
Point Correlation Function ◽  
Event Shapes ◽  
A Charge ◽  
Conserved Currents

Abstract We present a method for calculating event shapes in QCD based on correlation functions of conserved currents. The method has been previously applied to the maximally supersymmetric Yang-Mills theory, but we demonstrate that supersymmetry is not essential. As a proof of concept, we consider the simplest example of a charge-charge correlation at one loop (leading order). We compute the correlation function of four electromagnetic currents and explain in detail the steps needed to extract the event shape from it. The result is compared to the standard amplitude calculation. The explicit four-point correlation function may also be of interest for the CFT community.

scholarly journals Correlation functions in finite temperature CFT and black hole singularities

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
D. Rodriguez-Gomez ◽  
J.G. Russo
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Correlation Functions ◽  
Finite Temperature ◽  
Proper Time ◽  
Black Brane ◽  
Point Function ◽  
Black Hole Singularity ◽  
Point Correlation ◽  
Scaling Dimension

Abstract We compute thermal 2-point correlation functions in the black brane AdS5 background dual to 4d CFT’s at finite temperature for operators of large scaling dimension. We find a formula that matches the expected structure of the OPE. It exhibits an exponentiation property, whose origin we explain. We also compute the first correction to the two-point function due to graviton emission, which encodes the proper time from the event horizon to the black hole singularity.

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