Modeling CMB lensing cross correlations with CLEFT

Modi, Chirag; White, Martin; Vlah, Zvonimir

doi:10.1088/1475-7516/2017/08/009

Cited by 55 publications

(75 citation statements)

References 176 publications

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“…However, this assumption increasingly breaks down as dynamics and bias become nonlinear at low redshift and high mass ( Fig. 4; see also Modi et al 2017;Wilson & White 2019). The model of Eq.…”

Section: Common Bias Modelmentioning

confidence: 99%

Simulations and symmetries

Modi

Chen

White

2020

Monthly Notices of the Royal Astronomical Society

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We investigate the range of applicability of a model for the real-space power spectrum based on N-body dynamics and a (quadratic) Lagrangian bias expansion. This combination uses the highly accurate particle displacements that can be efficiently achieved by modern N-body methods with a symmetries-based bias expansion which describes the clustering of any tracer on large scales. We show that at low redshifts, and for moderately biased tracers, the substitution of N-body-determined dynamics improves over an equivalent model using perturbation theory by more than a factor of two in scale, while at high redshifts and for highly biased tracers the gains are more modest. This hybrid approach lends itself well to emulation. By removing the need to identify halos and subhalos, and by not requiring any galaxy-formation-related parameters to be included, the emulation task is significantly simplified at the cost of modeling a more limited range in scale.

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Section: Common Bias Modelmentioning

confidence: 99%

Simulations and symmetries

Modi

Chen

White

2020

Monthly Notices of the Royal Astronomical Society

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“…Similarly to the case of biased tracers, the EFT [47,62] provides a standard expansion for the matter field, i.e. what is needed to make theoretical predictions of gravitational lensing (e.g [63,64]). Up to third order, this is given by…”

Section: Review Of Bias Expansion For Scalar Tracersmentioning

confidence: 99%

An EFT description of galaxy intrinsic alignments

Vlah

Chisari

Schmidt

2020

J. Cosmol. Astropart. Phys.

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146

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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.

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“…In order to optimize what can be learned from the surveys mentioned above, theoretical predictions in the mildly and fully non-linear regimes are also needed. Previous work has suggested that perturbative models can accurately predict the clustering of biased tracers to a significant fraction of the nonlinear scale k nl = Σ −1 at high z [55][56][57][58][59], where Σ is mean square one-dimensional displacement in the Zeldovich approximation given by with P L the linear theory power spectrum. For high redshift tracers such as HI, perturbative models with their sophisticated biasing schemes become more useful due to increasing complexity of bias and decreasing non-linearity of the matter field as we go further back in time [59].…”

Section: Hi Clusteringmentioning

confidence: 99%

“…Previous work has suggested that perturbative models can accurately predict the clustering of biased tracers to a significant fraction of the nonlinear scale k nl = Σ −1 at high z [55][56][57][58][59], where Σ is mean square one-dimensional displacement in the Zeldovich approximation given by with P L the linear theory power spectrum. For high redshift tracers such as HI, perturbative models with their sophisticated biasing schemes become more useful due to increasing complexity of bias and decreasing non-linearity of the matter field as we go further back in time [59]. While we leave a detailed study of modeling 21-cm signal with such models for future work, when more sophisticated models and more simulation volume could become available, here we will compare the clustering signal to the predictions of linear theory and 'Zeldovich effective field theory' (ZEFT [60]).…”

Section: Hi Clusteringmentioning

confidence: 99%

Intensity mapping with neutral hydrogen and the Hidden Valley simulations

Modi

Castorina

Feng

et al. 2019

J. Cosmol. Astropart. Phys.

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This paper introduces the HiddenValley simulations, a set of trillion-particle N-body simulations in gigaparsec volumes aimed at intensity mapping science. We present details of the simulations and their convergence, then specialize to the study of 21-cm fluctuations between redshifts 2 and 6. Neutral hydrogen is assigned to halos using three prescriptions, and we investigate the clustering in real and redshift-space at the 2-point level. In common with earlier work we find the bias of HI increases from near 2 at z = 2 to 4 at z = 6, becoming more scale dependent at high z.The level of scale-dependence and decorrelation with the matter field are as predicted by perturbation theory. Due to the low mass of the hosting halos, the impact of fingers of god is small on the range relevant for proposed 21-cm instruments. We show that baryon acoustic oscillations and redshift-space distortions could be well measured by such instruments. Taking advantage of the large simulation volume, we assess the impact of fluctuations in the ultraviolet background, which change HI clustering primarily at large scales.

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Modeling CMB lensing cross correlations with CLEFT

Cited by 55 publications

References 176 publications

Simulations and symmetries

Simulations and symmetries

An EFT description of galaxy intrinsic alignments

Intensity mapping with neutral hydrogen and the Hidden Valley simulations

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