Measuring the growth rate of structure around 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.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab212 ◽

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.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316010139 ◽

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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