A nulling strategy for modelling lensing convergence in cones with large deviation theory

Barthelemy, Alexandre; Codis, Sandrine; Uhlemann, Cora; Bernardeau, Francis; Gavazzi, R.

doi:10.1093/mnras/staa053

Cited by 41 publications

(78 citation statements)

References 83 publications

(105 reference statements)

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“…These estimators are inherited from cosmic microwave background (CMB) analyses, which probe the matter distribution of the early Universe. However, cosmic shear probes the recent Universe, where the matter distribution is more complex due to the nonlinear accretion of structures that creates non-Gaussian features in the matter field on small scales (e.g., Codis et al 2015; Barthelemy et al 2020). Two-point statistics fail to capture this non-Gaussian information and thus yield an incomplete description of the matter distribution at low redshift.…”

Section: Introductionmentioning

confidence: 99%

Probing dark energy with tomographic weak-lensing aperture mass statistics

Martinet

Harnois-Déraps

Jullo

et al. 2021

A&A

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We forecast and optimize the cosmological power of various weak-lensing aperture mass (Map) map statistics for future cosmic shear surveys, including peaks, voids, and the full distribution of pixels (1D Map). These alternative methods probe the non-Gaussian regime of the matter distribution, adding complementary cosmological information to the classical two-point estimators. Based on the SLICS and cosmo-SLICS N-body simulations, we build Euclid-like mocks to explore the S8 − Ωm − w0 parameter space. We develop a new tomographic formalism that exploits the cross-information between redshift slices (cross-Map) in addition to the information from individual slices (auto-Map) probed in the standard approach. Our auto-Map forecast precision is in good agreement with the recent literature on weak-lensing peak statistics and is improved by ∼50% when including cross-Map. It is further boosted by the use of 1D Map that outperforms all other estimators, including the shear two-point correlation function (γ-2PCF). When considering all tomographic terms, our uncertainty range on the structure growth parameter S8 is enhanced by ∼45% (almost twice better) when combining 1D Map and the γ-2PCF compared to the γ-2PCF alone. We additionally measure the first combined forecasts on the dark energy equation of state w0, finding a factor of three reduction in the statistical error compared to the γ-2PCF alone. This demonstrates that the complementary cosmological information explored by non-Gaussian Map map statistics not only offers the potential to improve the constraints on the recent σ8–Ωm tension, but also constitutes an avenue to understanding the accelerated expansion of our Universe.

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Section: Introductionmentioning

confidence: 99%

Probing dark energy with tomographic weak-lensing aperture mass statistics

Martinet

Harnois-Déraps

Jullo

et al. 2021

A&A

View full text Add to dashboard Cite

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“…The corrections are introduced by changing the mapping globally and for a source redshift zs = 1100 and an opening angle θ = 10 arcmin (ν goes from 1.4 to 6.7). sity fluctuations of σ 1), relying on numerical simulations (Uhlemann et al 2016;Barthelemy et al 2020). As a consequence, corrections arising from post-Born effects need only be computed for the tree-order skewness and included as such in the formalism.…”

Section: One-point Pdf Without 2 Nd Order Correctionsmentioning

confidence: 99%

“…and uses equation (14) of Barthelemy et al (2020) to get the uncorrected tree-order skewness, one can write the corrected convergence as…”

Section: C2 Post-born Effect On Each Lensmentioning

confidence: 99%

“…Given the promises of cosmic field PDFs, recently the one-point PDF of the lensing convergence in cones in the quasi-linear regime was modelled from first principles using large deviation theory in Barthelemy et al (2020) -which is strictly speaking equivalent to computing all the cumulants of the field at tree-order in perturbation theory as was shown in Bernardeau (1992) and Valageas (2002). However in Barthelemy et al (2020) the convergence was modelled as a weighted integral over the underlying non-linear density field -therefore assuming independent lenses -along the un-perturbed line-of-sight. Hence, two ingredients were neglected: i) couplings between the lenses which state that the combination of lenses in geometrical optics is not lin-ear, and ii) the fact that background lenses are themselves lensed by foreground lenses, thus changing the overall trajectory of light rays.…”

Section: Introductionmentioning

confidence: 99%

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Post-Born corrections to the one-point statistics of (CMB) lensing convergence obtained via large deviation theory

Barthelemy

Codis

Bernardeau

2020

Monthly Notices of the Royal Astronomical Society

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Weak lensing of galaxies and CMB photons through the large-scale structure of the Universe is one of the most promising cosmological probes with upcoming experiments dedicated to its measurements such as Euclid/LSST and CMB Stage 4 experiments. With increasingly precise measurements, there is a dire need for accurate theoretical predictions. In this work, we focus on higher order statistics of the weak lensing convergence field, namely its cumulants such as skewness and kurtosis and its onepoint probability distribution (PDF), and we quantify using perturbation theory the corrections coming from post-Born effects, meaning beyond the straight-line and independent lenses approximations. At first order, two such corrections arise: lens-lens couplings and geodesic deviation. Though the corrections are small for low source redshifts (below a few percents) and therefore for galaxy lensing, they become important at higher redshifts, notably in the context of CMB lensing, where the non-gaussianities computed from tree-order perturbation theory are found to be of the same order as the signal itself. We include these post-Born corrections on the skewness into a prediction for the one-point convergence PDF obtained with large deviation theory and successfully test these results against numerical simulations. The modelled PDF is indeed shown to perform better than the percent for apertures above ∼ 10 arcminutes and typically in the three sigmas region around the mean.

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“…The resulting deflection angles are in extremely good agreement with the Born approximation. Although this does not test for higherorder effects such as lens-lens coupling, it still constitutes a simple test demonstrating the smallness of post-Born terms (2) some tests have already been performed in the literature [54,55], seemingly coming to the conclusion that post-Born terms are quite negligible for galaxy lensing.…”

Section: Born Approximationmentioning

confidence: 99%

Accurate analytic model for the thermal Sunyaev-Zel’dovich one-point probability distribution function

2019

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Non-Gaussian statistics of late-time cosmological fields contain information beyond that captured in the power spectrum. Here we focus on one such example: the one-point probability distribution function (PDF) of the thermal Sunyaev-Zel'dovich (tSZ) signal in maps of the cosmic microwave background (CMB). It has been argued that the one-point PDF is a near-optimal statistic for cosmological constraints from the tSZ signal, as most of the constraining power in tSZ N -point functions is contained in their amplitudes (rather than their shapes), which probe differently-weighted integrals over the halo mass function. In this paper, we develop a new analytic halo model for the tSZ PDF, discarding simplifying assumptions made in earlier versions of this approach. In particular, we account for effects due to overlaps of the tSZ profiles of different halos, as well as effects due to the clustering of halos. We verify the accuracy of our analytic model via comparison to numerical simulations. We demonstrate that this more accurate model is necessary for the analysis of the tSZ PDF in upcoming CMB experiments. The novel formalism developed here may be useful in modeling the one-point PDF of other cosmological observables, such as the weak lensing convergence field.

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A nulling strategy for modelling lensing convergence in cones with large deviation theory

Cited by 41 publications

References 83 publications

Probing dark energy with tomographic weak-lensing aperture mass statistics

Probing dark energy with tomographic weak-lensing aperture mass statistics

Post-Born corrections to the one-point statistics of (CMB) lensing convergence obtained via large deviation theory

Accurate analytic model for the thermal Sunyaev-Zel’dovich one-point probability distribution function

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