The bispectrum in the Effective Field Theory of Large Scale Structure

Baldauf, Tobias; Mercolli, Lorenzo; Mirbabayi, Mehrdad; Pajer, Enrico

doi:10.1088/1475-7516/2015/05/007

Cited by 168 publications

(313 citation statements)

References 69 publications

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“…Combining these improvements leads to a model to describe the 2-point statistics with accuracy close to 1%. Although some progress have been made [19][20][21][22][23][24][25][26][27][28][29], we have not seen a similar improvement for higher-order statistics.…”

Section: Introductioncontrasting

confidence: 69%

Dark matter and halo bispectrum in redshift space: theory and applications

Gil-Marín

Wagner

Noreña

et al. 2014

J. Cosmol. Astropart. Phys.

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Abstract. We present a phenomenological modification of the standard perturbation theory prediction for the bispectrum in redshift space that allows us to extend the model to mildly non-linear scales over a wide range of redshifts, z ≤ 1.5. Our model require 18 free parameters that are fitted to N-body simulations using the shapes k 2 /k 1 = 1, 1.5, 2.0, 2.5. We find that we can describe the bispectrum of dark matter particles with ∼ 5% accuracy for k i 0.10 h/Mpc at z = 0, for k i 0.15 h/Mpc at z = 0.5, for k i 0.17 h/Mpc at z = 1.0 and for k i 0.20 h/Mpc at z = 1.5. For very squeezed triangles with k 1 = k 2 0.1 hMpc −1 and k 3 ≤ 0.02 hMpc −1 , however, neither SPT nor the proposed fitting formula are able to describe the measured dark matter bispectrum with this accuracy. We show that the fitting formula is sufficiently general that can be applied to other intermediate shapes such as k 2 /k 1 = 1.25, 1.75, and 2.25. We also test that the fitting formula is able to describe with similar accuracy the bispectrum of cosmologies with different Ω m , in the range 0.2 Ω m 0.4, and consequently with different values of the logarithmic grow rate f at z = 0, 0.4 f (z = 0) 0.6. We apply this new formula to recover the bias parameters, f and σ 8 , by combining the redshift space power spectrum monopole and quadrupole with the bispectrum monopole for both dark matter particles and haloes. We find that the combination of these three statistics can break the degeneracy between b 1 , f and σ 8 . For dark matter particles the new model can be used to recover f and σ 8 with ∼ 1% accuracy. For dark matter haloes we find that f and σ 8 present larger systematic shifts, ∼ 10%. The systematic offsets arise because of limitations in the modelling of the interplay between bias and redshift space distortions, and represent a limitation as the statistical errors of forthcoming surveys reach this level. Conveniently, we find that these residual systematics are mitigated for combinations of parameters. In particular, the quantity f σ 8 is still recovered with ∼ 1% accuracy for the particular halo population and cosmology studied. The improvement on the modelling of the bispectrum presented in this paper will be useful for extracting information from current and future galaxy surveys.

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Section: Introductioncontrasting

confidence: 69%

Dark matter and halo bispectrum in redshift space: theory and applications

Gil-Marín

Wagner

Noreña

et al. 2014

J. Cosmol. Astropart. Phys.

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“…It is convenient to decompose the velocity field into its gradient and curl pieces. At the order we will work in this paper only the gradient component will be relevant, thus the stresses we need to model only enter through a scalar quantity: The case of the one loop bispectrum has already been considered in the literature [18,19]. In that case the second order counterterms are needed.…”

Section: The Eft Of Lssmentioning

confidence: 99%

“…In practice however, with current simulations there are significant degeneracies among these different parameters. In practice, making an ansatz for the ratios, scaling all counterterms by the same amplitude and fitting for this overall amplitude parameter, seems good enough to explain simulation measurements [18]. In this paper we are interested in performing a two-loop calculation for the power spectrum and thus we would have to model the stresses up to third order in the fields.…”

Section: The Eft Of Lssmentioning

confidence: 99%

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Effective field theory of large scale structure at two loops: The apparent scale dependence of the speed of sound

2015

Self Cite

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We study the Effective Field Theory of Large Scale Structure for cosmic density and momentum fields. We show that the finite part of the two-loop calculation and its counterterms introduce an apparent scale dependence for the leading order parameter c 2 s of the EFT starting at k = 0.1 hMpc −1 . These terms limit the range over which one can trust the one-loop EFT calculation at the 1% level to k < 0.1 hMpc −1 at redshift z = 0. We construct a well motivated one parameter ansatz to fix the relative size of the one-and two-loop counterterms using their high-k sensitivity. Although this one parameter model is a very restrictive choice for the counterterms, it explains the apparent scale dependence of c 2 s seen in simulations. It is also able to capture the scale dependence of the density power spectrum up to k ≈ 0.3 hMpc −1 at the 1% level at redshift z = 0. Considering a simple scheme for the resummation of large scale motions, we find that the two loop calculation reduces the need for this IR-resummation at k < 0.2 hMpc −1 . Finally, we extend our calculation to momentum statistics and show that the same one parameter model can also describe density-momentum and momentum-momentum statistics.

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“…An effective field theory description of the large-scale structure has been studied to constrain the dark matter three-point statistics (see Angulo et al 2014;Baldauf et al 2014). Thereafter, Kitaura et al (2014) found that a density threshold is essential to accurately model the halo three-point statistics.…”

Section: Density Threshold and Saturationmentioning

confidence: 99%

EZmocks: extending the Zel'dovich approximation to generate mock galaxy catalogues with accurate clustering statistics

Chuang

Kitaura

Prada

et al. 2014

Monthly Notices of the Royal Astronomical Society

170

152

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We present a new methodology to generate mock halo or galaxy catalogues, which have accurate clustering properties, nearly indistinguishable from full N -body solutions, in terms of the one-point, two-point, and three-point statistics. In particular, the agreement is remarkable, within 1% up to k = 0.55 h Mpc −1 and down to r = 10 h −1 Mpc, for the power spectrum and two-point correlation function respectively, while the bispectrum agrees in general within 20% for different scales and shapes. Our approach is based on the Zel'dovich approximation, however, effectively including with the simple prescriptions the missing physical ingredients, and stochastic scale-dependent, non-local and nonlinear biasing contributions. The computing time and memory required to produce one mock is similar to that using the log-normal model. With high accuracy and efficiency, the effective Zel'dovich approximation mocks (EZmocks) provide a reliable and practical method to produce massive mock galaxy catalogues for the analysis of large-scale structure measurements.

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The bispectrum in the Effective Field Theory of Large Scale Structure

Cited by 168 publications

References 69 publications

Dark matter and halo bispectrum in redshift space: theory and applications

Dark matter and halo bispectrum in redshift space: theory and applications

Effective field theory of large scale structure at two loops: The apparent scale dependence of the speed of sound

EZmocks: extending the Zel'dovich approximation to generate mock galaxy catalogues with accurate clustering statistics

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