Baryonic effects for weak lensing. Part I. Power spectrum and covariance matrix

Schneider, Aurel; Stoira, Nicola; Réfrégier, Alexandre; Weiss, Andreas J.; Knabenhans, Mischa; Stadel, Joachim; Teyssier, Romain

doi:10.1088/1475-7516/2020/04/019

Cited by 81 publications

(77 citation statements)

References 73 publications

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“…This was shown to be a good approximation in van Daalen et al ( 2020) by running hydro-simulations given the span of cosmology from WMAP 2009 (Hinshaw et al 2013) to Planck 2015 (Planck Collaboration et al 2016). Schneider et al (2020) also showed that ignoring the coupling between baryon and cosmology would be valid for future stage IV weak lensing experiments. We adopt the fiducial flat-ΛCDM cosmology shown in Table 1.…”

Section: Modelling the Theoretical Error Covariancementioning

confidence: 93%

Mitigating baryonic effects with a theoretical error covariance

Moreira

Andrade-Oliveira

Fang

et al. 2021

Monthly Notices of the Royal Astronomical Society

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One of the primary sources of uncertainties in modeling the cosmic-shear power spectrum on small scales is the effect of baryonic physics. Accurate cosmology for Stage-IV surveys requires knowledge of the matter power spectrum deep in the nonlinear regime at the percent level. Therefore, it is important to develop reliable mitigation techniques to take into account baryonic uncertainties if information from small scales is to be considered in the cosmological analysis. In this work, we develop a new mitigation method for dealing with baryonic physics for the case of the shear angular power spectrum. The method is based on an augmented covariance matrix that incorporates baryonic uncertainties informed by hydrodynamical simulations. We use the results from 13 hydrodynamical simulations and the residual errors arising from a fit to a ΛCDM model using the extended halo model code HMCode to account for baryonic physics. These residual errors are used to model a so-called theoretical error covariance matrix that is added to the original covariance matrix. In order to assess the performance of the method, we use the 2D tomographic shear from four hydrodynamical simulations that have different extremes of baryonic parameters as mock data and run a likelihood analysis comparing the residual bias on Ωm and σ8 of our method and the HMCode for an LSST-like survey. We use different modelling of the theoretical error covariance matrix to test the robustness of the method. We show that it is possible to reduce the bias in the determination of the tested cosmological parameters at the price of a modest decrease in the precision.

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Section: Modelling the Theoretical Error Covariancementioning

confidence: 93%

Mitigating baryonic effects with a theoretical error covariance

Moreira

Andrade-Oliveira

Fang

et al. 2021

Monthly Notices of the Royal Astronomical Society

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show abstract

“…Although improving the gravity-only predictions on small scales will be an important task, baryons have a much more important impact on these scales and thus for the overall accuracy of the predictions. To address this, also emulators have been built based on physically-motivated models for baryonic effects, which claim that they can also obtain few percent accuracy (Schneider et al 2020;Arico `et al 2021a). Although they are close to the target accuracy, they are likely only sufficient for the first round of data analysis of upcoming surveys, but continued improvement in precision will be needed.…”

Section: Challenges For Cosmological Predictionsmentioning

confidence: 99%

Large-scale dark matter simulations

Angulo

Hahn

2022

Living Rev Comput Astrophys

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We review the field of collisionless numerical simulations for the large-scale structure of the Universe. We start by providing the main set of equations solved by these simulations and their connection with General Relativity. We then recap the relevant numerical approaches: discretization of the phase-space distribution (focusing on N-body but including alternatives, e.g., Lagrangian submanifold and Schrödinger–Poisson) and the respective techniques for their time evolution and force calculation (direct summation, mesh techniques, and hierarchical tree methods). We pay attention to the creation of initial conditions and the connection with Lagrangian Perturbation Theory. We then discuss the possible alternatives in terms of the micro-physical properties of dark matter (e.g., neutralinos, warm dark matter, QCD axions, Bose–Einstein condensates, and primordial black holes), and extensions to account for multiple fluids (baryons and neutrinos), primordial non-Gaussianity and modified gravity. We continue by discussing challenges involved in achieving highly accurate predictions. A key aspect of cosmological simulations is the connection to cosmological observables, we discuss various techniques in this regard: structure finding, galaxy formation and baryonic modelling, the creation of emulators and light-cones, and the role of machine learning. We finalise with a recount of state-of-the-art large-scale simulations and conclude with an outlook for the next decade.

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“…Systematic effects can be mitigated by excluding the small scales (k 10 −1 h/Mpc) when fitting the measured power spectra, although that comes at the price of greatly increased uncertainties in the resulting cosmological parameters. Constraints on extended cosmologies, such as massive neutrinos, variable dark energy equation of state, or chameleon gravity, require sensitivity on smaller scales, and their effect is strongly degenerate with that of baryonic physics [326,327].…”

Section: Impact On Cosmological Probesmentioning

confidence: 99%

Feedback from Active Galactic Nuclei in Galaxy Groups

et al. 2021

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The co-evolution between supermassive black holes and their environment is most directly traced by the hot atmospheres of dark matter halos. The cooling of the hot atmosphere supplies the central regions with fresh gas, igniting active galactic nuclei (AGN) with long duty cycles. Outflows from the central engine tightly couple with the surrounding gaseous medium and provide the dominant heating source preventing runaway cooling by carving cavities and driving shocks across the medium. The AGN feedback loop is a key feature of all modern galaxy evolution models. Here, we review our knowledge of the AGN feedback process in the specific context of galaxy groups. Galaxy groups are uniquely suited to constrain the mechanisms governing the cooling–heating balance. Unlike in more massive halos, the energy that is supplied by the central AGN to the hot intragroup medium can exceed the gravitational binding energy of halo gas particles. We report on the state-of-the-art in observations of the feedback phenomenon and in theoretical models of the heating-cooling balance in galaxy groups. We also describe how our knowledge of the AGN feedback process impacts galaxy evolution models and large-scale baryon distributions. Finally, we discuss how new instrumentation will answer key open questions on the topic.

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Baryonic effects for weak lensing. Part I. Power spectrum and covariance matrix

Cited by 81 publications

References 73 publications

Mitigating baryonic effects with a theoretical error covariance

Mitigating baryonic effects with a theoretical error covariance

Large-scale dark matter simulations

Feedback from Active Galactic Nuclei in Galaxy Groups

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