Impact of baryons in cosmic shear analyses with tomographic aperture mass statistics
Abstract
NonGaussian cosmic shear statistics based on weaklensing aperture mass (M_{ap}) maps can outperform the classical shear twopoint correlation function (γ2PCF) 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 KiDS450 and DESY1 surveys and a Euclidlike 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 S_{8}, the matter density parameter Ω_{m}, and the dark energy equation of state w_{0} using the SLICS and cosmoSLICS sets of darkmatteronly simulations. We report a negative bias of a few percent on S_{8} and Ω_{m} and also measure a positive bias of the same level on w_{0} when including a tomographic decomposition. These biases reach ∼5% when combining M_{ap} statistics with the γ2PCF 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 smallscale information to a point where the constraints would no longer be competitive.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 April 2021
 DOI:
 10.1051/00046361/202040155
 arXiv:
 arXiv:2012.09614
 Bibcode:
 2021A&A...648A.115M
 Keywords:

 cosmology: observations;
 dark energy;
 largescale structure of Universe;
 dark matter;
 gravitational lensing: weak;
 surveys;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 12 pages, 9 figures, matching the version accepted in A&