We present a joint likelihood analysis of the real-space power spectrum and bispectrum measured from a variety of halo and galaxy mock catalogs. A novel aspect of this work is the inclusion of ...nonlinear triangle configurations for the bispectrum, made possible by a complete next-to-leading order ("one-loop") description of galaxy bias, as is already common practice for the power spectrum. Based on the goodness of fit and the unbiasedness of the parameter posteriors, we accomplish a stringent validation of this model compared to the leading order ("tree-level") bispectrum. Using measurement uncertainties that correspond to an effective survey volume of 6 (Gpc/h)3, we determine that the one-loop corrections roughly double the applicable range of scales, from ∼0.17 h/Mpc (tree level) to ∼0.3 h/Mpc. This converts into a 1.5–2x improvement on constraints of the linear bias parameter at fixed cosmology, and a 1.5–2.4x shrinkage of uncertainties on the amplitude of fluctuations As, which clearly demonstrates the benefit of extracting information from nonlinear scales despite having to marginalize over a larger number of bias parameters. Besides, our precise measurements of galaxy bias parameters up to fourth order allow for thorough comparisons to coevolution relations, showing excellent agreement for all contributions generated by the nonlocal action of gravity. Using these relations in the likelihood analysis does not compromise the model validity and is crucial for obtaining the quoted improvements on As. We also analyzed the impact of higher-derivative and scale-dependent stochastic terms, finding that for a subset of our tracers the former can boost the performance of the tree-level model with constraints on As that are only slightly degraded compared to the one-loop model.
MPTbreeze: a fast renormalized perturbative scheme Crocce, Martín; Scoccimarro, Román; Bernardeau, Francis
Monthly notices of the Royal Astronomical Society,
11 December 2012, Volume:
427, Issue:
3
Journal Article
Peer reviewed
Open access
ABSTRACT
We put forward and test a simple description of multipoint propagators (MP), which serve as building blocks to calculate the non‐linear matter power spectrum. On large scales these ...propagators reduce to the well‐known kernels in standard perturbation theory, while at smaller scales they are suppressed due to non‐linear couplings. Through extensive testing with numerical simulations we find that this decay is characterized by the same damping scale for both two‐ and three‐point propagators. In turn this transition can be well modelled with resummation results that exponentiate one‐loop computations. For the first time, we measure the four components of the non‐linear (two‐point) propagator using dedicated simulations started from two independent random Gaussian fields for positions and velocities, verifying in detail the fundamentals of propagator resummation.
We use these results to develop an implementation of the MP expansion for the non‐linear power spectrum that only requires seconds to evaluate at baryon acoustic oscillations (BAO) scales. To test it we construct six suites of large numerical simulations with different cosmologies. From these and LasDamas runs we show that the non‐linear power spectrum can be described at the ≲ 2 per cent level at BAO scales for redshifts in the range 0–2.5. We make a public release of the MPTbreeze code with the hope that it can be useful to the community.
We explore the cosmological implications of anisotropic clustering measurements in configuration space of the final galaxy samples from Data Release 12 of the Sloan Digital Sky Survey III Baryon ...Oscillation Spectroscopic Survey. We implement a new detailed modelling of the effects of non-linearities, bias and redshift-space distortions that can be used to extract unbiased cosmological information from our measurements for scales ... We combined the information from Baryon Oscillation Spectroscopic Survey (BOSS) with the latest cosmic microwave background (CMB) observations and Type Ia supernovae samples and found no significant evidence for a deviation from the ... cold dark matter (...CDM) cosmological model. In particular, these data sets can constrain the dark energy equation-of-state parameter to ... when to be assumed time independent, the curvature of the Universe to ... and the sum of the neutrino masses to ... at 95 per cent confidence levels. We explore the constraints on the growth rate of cosmic structures assuming ... and obtain ..., in good agreement with the predictions of general relativity of ... We compress the information of our clustering measurements into constraints on the parameter combinations ... and 0.61 with their respective covariance matrices and find good agreement with the predictions for these parameters obtained from the best-fitting ...CDM model to the CMB data from the Planck satellite. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others by Alam et al. to produce the final cosmological constraints from BOSS. (ProQuest: ... denotes formulae/symbols omitted.)
We study the impact of setting initial conditions in numerical simulations using the standard procedure based on the Zel'dovich approximation (ZA). As it is well known from the perturbation theory, ...ZA initial conditions have incorrect second- and higher-order growth and therefore excite long-lived transients in the evolution of the statistical properties of density and velocity fields. We also study the improvement brought by using more accurate initial conditions based on second-order Lagrangian perturbation theory (2LPT). We show that 2LPT initial conditions reduce transients significantly and thus are much more appropriate for numerical simulations devoted to precision cosmology. Using controlled numerical experiments with ZA and 2LPT initial conditions, we show that simulations started at redshift zi= 49 using the ZA underestimate the power spectrum in the non-linear regime by about 2, 4 and 8 per cent at z= 0, 1, and 3, respectively, whereas the mass function of dark matter haloes is underestimated by 5 per cent at m= 1015 M⊙ h−1 (z= 0) and 10 per cent at m= 2 × 1014 M⊙ h−1 (z= 1). The clustering of haloes is also affected to the few per cent level at z= 0. These systematics effects are typically larger than statistical uncertainties in recent mass function and power spectrum fitting formulae extracted from numerical simulations. At large scales, the measured transients in higher-order correlations can be understood from first principle calculations based on perturbation theory.
We compute the covariance of the galaxy power spectrum multipoles in perturbation theory, including the effects of nonlinear evolution, nonlinear and nonlocal bias, radial redshift-space distortions, ...arbitrary survey window, and shot noise. We rewrite the power spectrum FKP estimator in terms of the usual windowed galaxy fluctuations and the fluctuations in the number of galaxies inside the survey volume. We show that this leads to a stronger supersample covariance than assumed in the literature and causes a substantial leakage of Gaussian information. We decompose the covariance matrix into several contributions that provide an insight into its behavior for different biased tracers. We show that for realistic surveys, the covariance of power spectrum multipoles is already dominated by shot noise and super survey mode coupling in the weakly nonlinear regime. Both these effects can be accurately modeled analytically, making a perturbative treatment of the covariance very compelling. Our method allows for the covariance to be varied as a function of cosmology and bias parameters very efficiently, with survey geometry entering as fixed kernels that can be computed separately using fast fourier transforms (FFTs). We find excellent agreement between our analytic covariance and that estimated from BOSS DR12 Patchy mock catalogs in the whole range we tested, up to k = 0.6 h/ Mpc. This bodes well for application to future surveys such as DESI and Euclid.
Abstract
We apply the Alcock–Paczyński (AP) test to stacked voids identified using the final data release (DR12) of the Baryon Oscillation Spectroscopic Survey (BOSS). We also use 1000 mock galaxy ...catalogs that match the geometry, density, and clustering properties of the BOSS sample in order to characterize the statistical uncertainties of our measurements and take into account systematic errors such as redshift space distortions. For both BOSS data and mock catalogs, we use the ZOBOV algorithm to identify voids, we stack together all voids with effective radii of
in the redshift range of 0.43–0.7, and we accurately measure the shape of the stacked voids. Our tests with the mock catalogs show that we measure the stacked void ellipticity with a statistical precision of 2.6%. The stacked voids in redshift space are slightly squashed along the line of sight, consistent with previous studies. We repeat this measurement of stacked void shape in the BOSS data, assuming several values of
within the flat
model, and we compare this to the mock catalogs in redshift space to perform the AP test. We obtain a constraint of
at the 68% confidence level from the AP test. We discuss the sources of statistical and systematic noise that affect the constraining power of this method. In particular, we find that the measured ellipticity of stacked voids changes more weakly with cosmology than the standard AP prediction, leading to significantly weaker constraints. We discuss how constraints will improve in future surveys with larger volumes and densities.
Abstract
We extract cosmological information from the anisotropic power-spectrum measurements from the recently completed Baryon Oscillation Spectroscopic Survey (BOSS), extending the concept of ...clustering wedges to Fourier space. Making use of new fast-Fourier-transform-based estimators, we measure the power-spectrum clustering wedges of the BOSS sample by filtering out the information of Legendre multipoles ℓ > 4. Our modelling of these measurements is based on novel approaches to describe non-linear evolution, bias and redshift-space distortions, which we test using synthetic catalogues based on large-volume N-body simulations. We are able to include smaller scales than in previous analyses, resulting in tighter cosmological constraints. Using three overlapping redshift bins, we measure the angular-diameter distance, the Hubble parameter and the cosmic growth rate, and explore the cosmological implications of our full-shape clustering measurements in combination with cosmic microwave background and Type Ia supernova data. Assuming a Λ cold dark matter (ΛCDM) cosmology, we constrain the matter density to $\Omega _{\mathrm{M}}= 0.311_{-0.010}^{+0.009}$ and the Hubble parameter to $H_0 = 67.6_{-0.6}^{+0.7} \, \, \mathrm{km \, s^{-1} \, Mpc^{-1}}$, at a confidence level of 68 per cent. We also allow for non-standard dark energy models and modifications of the growth rate, finding good agreement with the ΛCDM paradigm. For example, we constrain the equation-of-state parameter to $w = -1.019_{-0.039}^{+0.048}$. This paper is part of a set that analyses the final galaxy-clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS.
PDF
