scholarly journals Improving estimates of the growth rate using galaxy–velocity correlations: a simulation study

2021 ◽  
Vol 502 (2) ◽  
pp. 2087-2096
Author(s):  
Ryan J Turner ◽  
Chris Blake ◽  
Rossana Ruggeri
Keyword(s):  
Growth Rate ◽  
Correlation Function ◽  
Large Scale ◽  
Cross Correlation ◽  
Cross Correlation Function ◽  
Velocity Autocorrelation Function ◽  
Simulation Code ◽  
The Galaxy ◽  
Galaxy Bias ◽  
Correlation Statistics

ABSTRACT We present an improved framework for estimating the growth rate of large-scale structure, using measurements of the galaxy–velocity cross-correlation in configuration space. We consider standard estimators of the velocity autocorrelation function, ψ1 and ψ2, the two-point galaxy correlation function, ξgg, and introduce a new estimator of the galaxy–velocity cross-correlation function, ψ3. By including pair counts measured from random catalogues of velocities and positions sampled from distributions characteristic of the true data, we find that the variance in the galaxy–velocity cross-correlation function is significantly reduced. Applying a covariance analysis and χ2 minimization procedure to these statistics, we determine estimates and errors for the normalized growth rate fσ8 and the parameter β = f/b, where b is the galaxy bias factor. We test this framework on mock hemisphere data sets for redshift z < 0.1 with realistic velocity noise constructed from the l-picola simulation code, and find that we are able to recover the fiducial value of fσ8 from the joint combination of ψ1 + ψ2 + ψ3 + ξgg, with 15 per cent accuracy from individual mocks. We also recover the fiducial fσ8 to within 1σ regardless of the combination of correlation statistics used. When we consider all four statistics together we find that the statistical uncertainty in our measurement of the growth rate is reduced by $59{{\ \rm per\ cent}}$ compared to the same analysis only considering ψ2, by $53{{\ \rm per\ cent}}$ compared to the same analysis only considering ψ1, and by $52{{\ \rm per\ cent}}$ compared to the same analysis jointly considering ψ1 and ψ2.

scholarly journals Measuring the growth rate of structure around cosmic voids

2014 ◽  
Vol 11 (S308) ◽  
pp. 571-574
Author(s):  
A. J. Hawken ◽  
D. Michelett ◽  
B. Granett ◽  
A. Iovino ◽  
L. Guzzo
Keyword(s):  
Growth Rate ◽  
Correlation Function ◽  
Cross Correlation ◽  
Cross Correlation Function ◽  
Redshift Survey ◽  
Cosmic Voids

AbstractUsing an algorithm based on searching for empty spheres we identified 245 voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We show how by modelling the anisotropic void-galaxy cross correlation function we can probe the growth rate of structure.

scholarly journals Constraining the growth rate of structure with phase correlations

2020 ◽  
Vol 497 (2) ◽  
pp. 1765-1790
Author(s):  
Joyce Byun ◽  
Felipe Oliveira Franco ◽  
Cullan Howlett ◽  
Camille Bonvin ◽  
Danail Obreschkow
Keyword(s):  
Growth Rate ◽  
Correlation Function ◽  
Power Spectrum ◽  
Large Scale ◽  
Large Scale Structure ◽  
Density Field ◽  
Galaxy Surveys ◽  
Additional Information ◽  
Forecasting Method ◽  
The Galaxy

ABSTRACT We show that correlations between the phases of the galaxy density field in redshift space provide additional information about the growth rate of large-scale structure that is complementary to the power-spectrum multipoles. In particular, we consider the multipoles of the line correlation function (LCF), which correlates phases between three collinear points, and use the Fisher forecasting method to show that the LCF multipoles can break the degeneracy between the measurement of the growth rate of structure f and the amplitude of perturbations σ8 that is present in the power-spectrum multipoles at large scales. This leads to an improvement in the measurement of f and σ8 by up to 220 per cent for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{-1}$ and up to 50 per cent for $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{-1}$ at redshift z = 0.25, with respect to power-spectrum measurements alone for the upcoming generation of galaxy surveys like DESI and Euclid. The average improvements in the constraints on f and σ8 for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{-1}$ are ∼90 per cent for the DESI BGS sample with mean redshift $\overline{z}=0.25$, ∼40 per cent for the DESI ELG sample with $\overline{z}=1.25$, and ∼40 per cent for the Euclid Hα galaxies with $\overline{z}=1.3$. For $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{-1}$, the average improvements are ∼40 per cent for the DESI BGS sample and ∼20 per cent for both the DESI ELG and Euclid Hα galaxies.

scholarly journals Redshift-Space Distortions and f(z) from Group-Galaxy Correlations

2014 ◽  
Vol 11 (S308) ◽  
pp. 342-343
Author(s):  
F. G. Mohammad ◽  
S. de la Torre ◽  
L. Guzzo ◽  
D. Bianchi ◽  
J. A. Peacock
Keyword(s):  
Growth Rate ◽  
Correlation Function ◽  
Cross Correlation ◽  
Systematic Errors ◽  
Cross Correlation Function ◽  
Multipole Moments ◽  
Simulation Results ◽  
Group Galaxy

AbstractWe investigate the accuracy achievable on measurements of the the growth rate of structure f(z) using redshift-space distortions (RSD), when (a) these are measured on the group-galaxy cross correlation function; (b) the latter is expanded over a modified version of the conventional spherical armonics, “truncated multipole moments”. Simulation results give first indications that this combination can push systematic errors on f(z) below 3%, using scales r ⩾ 10h−1 Mpc.

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