Impact of baryons in cosmic shear analyses with tomographic aperture mass statistics

¹ Aix-Marseille Univ., CNRS, CNES, LAM, Marseille, France
e-mail: nicolas.martinet@lam.fr
² Dipartimento di Fisica, Sezione di Astronomia, Università di Trieste, Via Tiepolo 11, 34143 Trieste, Italy
³ INAF – Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34131 Trieste, Italy
⁴ IFPU – Institute for Fundamental Physics of the Universe, Via Beirut 2, 34151 Trieste, Italy
⁵ INFN – Sezione di Trieste, 34100 Trieste, Italy
⁶ Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
⁷ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
⁸ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
⁹ INFN – Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
¹⁰ University Observatory Munich, Scheinerstr. 1, 81679 Munchen, Germany
¹¹ Max-Planck Institut fur Astrophysik, Karl-Schwarzschild Str. 1, 85741 Garching, Germany

Received: 17 December 2020
Accepted: 15 February 2021

Abstract

NonGaussian cosmic shear statistics based on weak-lensing aperture mass (M_ap) maps can outperform the classical shear two-point correlation function (γ-2PCF) in terms of cosmological constraining power. However, reaching the full potential of these new estimators requires accurate modeling of the physics of baryons as the extra nonGaussian information mostly resides at small scales. We present one such modeling based on the Magneticum hydrodynamical simulation for the KiDS-450 and DES-Y1 surveys and a Euclid-like survey. We compute the bias due to baryons on the lensing PDF and the distribution of peaks and voids in M_ap maps and propagate it to the cosmological forecasts on the structure growth parameter S₈, the matter density parameter Ω_m, and the dark energy equation of state w₀ using the SLICS and cosmo-SLICS sets of dark-matter-only simulations. We report a negative bias of a few percent on S₈ and Ω_m and also measure a positive bias of the same level on w₀ when including a tomographic decomposition. These biases reach ∼5% when combining M_ap statistics with the γ-2PCF as these estimators show similar dependency on the AGN feedback. We verify that these biases constitute a less than 1σ shift on the probed cosmological parameters for current cosmic shear surveys. However, baryons need to be accounted for at the percentage level for future Stage IV surveys and we propose to include the uncertainty on the AGN feedback amplitude by marginalizing over this parameter using multiple simulations such as those presented in this paper. Finally, we explore the possibility of mitigating the impact of baryons by filtering the M_ap map but find that this process would require suppressing the small-scale information to a point where the constraints would no longer be competitive.