A robust measurement of the first higher-derivative bias of dark matter halos

148

171

We present a Markov-Chain Monte-Carlo (MCMC) forecast for the precision of neutrino mass and cosmological parameter measurements with a Euclidlike galaxy clustering survey. We use a complete perturbation theory model for the galaxy one-loop power spectrum and tree-level bispectrum, which includes bias, redshift space distortions, IR resummation for baryon acoustic oscillations and UV counterterms. The latter encapsulate various effects of short-scale dynamics which cannot be modeled within perturbation theory. Our MCMC procedure consistently computes the non-linear power spectra and bispectra as we scan over different cosmologies. The second ingredient of our approach is the theoretical error covariance which captures uncertainties due to higher-order non-linear corrections omitted in our model. Having specified characteristics of a Euclid-like spectroscopic survey, we generate and fit mock galaxy power spectrum and bispectrum likelihoods. Our results suggest that even under very agnostic assumptions about non-linearities and short-scale physics a future Euclid-like survey will be able to measure the sum of neutrino masses with a standard deviation of 28 meV. When combined with the most recent Planck likelihood, this uncertainty decreases to 19 meV. Reducing the theoretical error on the bispectrum down to the two-loop level marginally tightens the bound to 17 meV. 1 chudy@ms2.inr.ac.ru 2 mi1271@nyu.edu arXiv:1907.06666v1 [astro-ph.CO] 15 Jul 2019 exploit the potential of upcoming surveys will strongly depend on the understanding on these effects, which is not yet complete.Fortunately, the bulk of information about the neutrino free-streaming is encoded in mildly non-linear scales which can be robustly and systematically described within perturbation theory. One of the most popular approaches is Eulerian standard cosmological perturbation theory (SPT) [14]. The basic formulation of SPT, however, does not correctly capture the non-linear evolution of baryon acoustic oscillations (BAO) [15] and short-scale physics beyond the single-stream pressureless perfect fluid hydrodynamics [16][17][18]. These problems have been intensely studied in the recent years.First, it has been shown that the non-linear suppression and distortion of the BAO can be captured by a resummation of contributions describing the tidal effects of large-scale bulk flows. This procedure, called infrared (IR) resummation, is essential for an accurate description of the BAO and has been formulated within various theoretical frameworks [19][20][21][22][23][24][25]. We will adopt a systematic approach of [22,24] streamlined in the context of time-sliced perturbation theory [26].Second, we will use the effective field theory of large-scale structure (EFT) to account for the back-reaction of small scale nonlinearities on larger scales [17,27,28]. This approach removes the unphysical UV sensitivity of perturbation theory loop integrals and parameterizes the ignorance about short scale-dynamics by various effective operators in the equations of motion for ...

“…Note that a recent study [34] has found some deviations from this scaling. Now let us discuss the redshift space counterterms, which are dominated by the fingers-of-God effect.…”

Section: Parameter Definition Fiducial Value Hmentioning

confidence: 74%

“…As for the higher-derivative bias coefficient, the measurements from N-body simulations [34,78,101] suggest that it is an order-one quantity in units of [Mpc/h] 2 . Thus, we adopt the following fiducial value along with the time-dependence that corresponds to the one-loop contribution,…”

Section: Parameter Definition Fiducial Value Hmentioning

confidence: 99%

Measuring neutrino masses with large-scale structure: Euclid forecast with controlled theoretical error

Chudaykin

Ivanov

2019

148

171

“…In general, this expansion is controlled by the parameter (kR * ) 2 , where k is the wavenumber and R * is a spatial length scale that is specific to a given tracer. For halos, this scale is expected and found to be of order the Lagrangian radius [5,45,46], but for real galaxies it could be substantially larger (e.g., [47][48][49]), so that the ability to include higher-derivative bias operators is potentially important. Even for halos, Ref.…”

Section: Higher-derivative Biasmentioning

confidence: 99%

“…Several measurements of the effective sound speed have been presented in the literature [4,46,[59][60][61], most of which have been based on Eulerian perturbation theory. The closest comparison point is offered by [4].…”

Section: Lptmentioning

confidence: 99%

A rigorous EFT-based forward model for large-scale structure

Schmidt

Elsner

Jasche

et al. 2019

Self Cite

197

Conventional approaches to cosmology inference from galaxy redshift surveys are based on n-point functions, which are under rigorous perturbative control on sufficiently large scales. Here, we present an alternative approach, which employs a likelihood at the level of the galaxy density field. By integrating out small-scale modes based on effective-field theory arguments, we prove that this likelihood is under perturbative control if certain specific conditions are met. We further show that the information captured by this likelihood is equivalent to the combination of the next-to-leading order galaxy power spectrum, leadingorder bispectrum, and BAO reconstruction. Combined with MCMC sampling and MAP optimization techniques, our results allow for fully Bayesian cosmology inference from largescale structure that is under perturbative control. We illustrate this via a first demonstration of unbiased cosmology inference from nonlinear large-scale structure using this likelihood. In particular, we show unbiased estimates of the power spectrum normalization σ 8 from a catalog of simulated dark matter halos, where nonlinear information is crucial in breaking the b 1 − σ 8 degeneracy.

“…If the scale R * is larger than the spatial length scale (nonlinear scale) controlling the perturbative expansion, then one can correspondingly include higher-order derivative terms. This might be the case for very massive halos [66][67][68], for example, or due to radiative-transfer effects [69][70][71][72][73][74].…”

Section: Higher Derivativesmentioning

confidence: 99%

An EFT description of galaxy intrinsic alignments

Vlah

Chisari

Schmidt

2020

Self Cite

146

We present a general perturbative effective field theory (EFT) description of galaxy shape correlations, which are commonly known as intrinsic alignments. This rigorous approach extends current analytical modelling strategies in that it only relies on the equivalence principle. We present our results in terms of three-dimensional statistics for two-and three-point functions of both galaxy shapes and number counts. In case of the two-point function, we recover the well-known linear alignment result at leading order, but also present the full next-to-leading order expressions. In case of the three-point function we present leading order results for all the auto-and cross-correlations of galaxy shapes and densities. We use a spherical tensor basis to decompose the tensor perturbations in different helicity modes, which allows us to make use of isotropy and parity properties in the correlators. Combined with the results on projection presented in a forthcoming companion paper, our framework is directly applicable to accounting for intrinsic alignment contamination in weak lensing surveys, and to extracting cosmological information from intrinsic alignments. 42A.1 Two-point functions 44 A.2 Three-point functions 47 B Fields in Fourier space 50 B.1 Bias expansion and renormalisation of the one-loop power spectrum 55 B.2 Degeneracy of the bias operators 62 B.3 Bias expansion of the tree-level bispectrum 63 C Bias renormalisation for tensor fields 65 1 Explicitly, we writewhere the Dirac delta function ensures the total momentum conservation, and is a consequence of the statistical translation invariance.