Baryons, Neutrinos, Feedback and Weak Gravitational Lensing

Abstract

(Abridged) The effect of baryonic feedback on the dark matter mass distribution is generally considered to be a nuisance to weak gravitational lensing. Measurements of cosmological parameters are affected as feedback alters the cosmic shear signal on angular scales smaller than a few arcminutes. Recent progress on the numerical modelling of baryon physics has shown that this effect could be so large that, rather than being a nuisance, the effect can be constrained with current weak lensing surveys, hence providing an alternative astrophysical insight on one of the most challenging questions of galaxy formation. In order to perform our analysis, we construct an analytic fitting formula that describes the effect of the baryons on the mass power spectrum. This fitting formula is based on three scenarios of the OWL hydrodynamical simulations. It is specifically calibrated for $z<1.5$, where it models the simulations to an accuracy that is better than $2\%$ for scales $k<10 h\mbox{Mpc}^{-1}$ and better than $5\%$ for $10 < k < 100 h\mbox{Mpc}^{-1}$. Equipped with this precise tool, this paper presents the first constraint on baryonic feedback models using gravitational lensing data, from the Canada France Hawaii Telescope Lensing Survey (CFHTLenS). In this analysis, we show that the effect of neutrino mass on the mass power spectrum is degenerate with the baryonic feedback at small angular scales and cannot be ignored. Assuming a cosmology precision fixed by WMAP9, we find that a universe with no baryon feedback and massless neutrinos is rejected by the CFHTLenS lensing data with 96\% confidence. Our study shows that ongoing weak gravitational lensing surveys (KiDS, HSC and DES) will offer a unique opportunity to probe the physics of baryons at galactic scales, in addition to the expected constraints on the total neutrino mass.

12 pages, 7 figures, 3 tables

References in corpus (7)

• Why your model parameter confidences might be too optimistic -- unbiased estimation of the inverse covariance matrix
• Photometric redshift analysis in the Dark Energy Survey Science Verification data
• CFHTLenS: Cosmological constraints from a combination of cosmic shear two-point and three-point correlations
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Signs of neutrino mass in current cosmological datasets
• Analysis of two-point statistics of cosmic shear: III. Covariances of shear measures made easy
• Systematic errors in the measurement of neutrino masses due to baryonic feedback processes: Prospects for stage IV lensing surveys
• Neutrino mass from the Lyman-Alpha forest

Cited by in corpus (12)

• Fast likelihood-free cosmology with neural density estimators and active learning
• KiDS-450: The tomographic weak lensing power spectrum and constraints on cosmological parameters
• Full-sky Gravitational Lensing Simulation for Large-area Galaxy Surveys and Cosmic Microwave Background Experiments
• KiDS-450: Cosmological Constraints from Weak Lensing Peak Statistics - II: Inference from Shear Peaks using N-body Simulations
• Nuisance hardened data compression for fast likelihood-free inference
• Constraining $M_{\nu }$ with the Bispectrum II: The Total Information Content of the Galaxy Bispectrum
• A hydrodynamical halo model for weak-lensing cross correlations
• DEMNUni: comparing nonlinear power spectra prescriptions in the presence of massive neutrinos and dynamical dark energy
• Inference from the small scales of cosmic shear with current and future Dark Energy Survey data
• Consistency of cosmic shear analyses in harmonic and real space
• Higher order statistics of shear field: a machine learning approach
• $\alpha$-attractor dark energy in view of next-generation cosmological surveys