Baryonic effects for weak lensing. Part II. Combination with X-ray data and extended cosmologies

Aurel Schneider, Alexandre Refregier, Sebastian Grandis, Dominique Eckert, Nicola Stoira, Tomasz Kacprzak, Mischa Knabenhans, Joachim Stadel, Romain Teyssier

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


An accurate modelling of baryonic feedback effects is required to exploit the full potential of future weak-lensing surveys such as Euclid or LSST . In this second paper in a series of two, we combine Euclid-like mock data of the cosmic shear power spectrum with an eROSITA X-ray mock of the cluster gas fraction to run a combined likelihood analysis including both cosmological and baryonic parameters. Following the first paper of this series, the baryonic effects (based on the baryonic correction model of ref. [1]) are included in both the tomographic power spectrum and the covariance matrix. However, this time we assume the more realistic case of a ΛCDM cosmology with massive neutrinos and we consider several extensions of the currently favoured cosmological model. For the standard ΛCDM case, we show that including X-ray data reduces the uncertainties on the sum of the neutrino mass by ∼30 percent, while there is only a mild improvement on other parameters such as Ωm and σ8. As extensions of ΛCDM, we consider the cases of a dynamical dark energy model (wCDM), a f(R) gravity model (fRCDM), and a mixed dark matter model (ΛMDM) with both a cold and a warm/hot dark matter component. We find that combining weak-lensing with X-ray data only leads to a mild improvement of the constraints on the additional parameters of wCDM, while the improvement is more substantial for both fRCDM and ΛMDM . Ignoring baryonic effects in the analysis pipeline leads to significant false-detections of either phantom dark energy or a light subdominant dark matter component. Overall we conclude that for all cosmologies considered, a general parametrisation of baryonic effects is both necessary and sufficient to obtain tight constraints on cosmological parameters.

Original languageEnglish (US)
Article number020
JournalJournal of Cosmology and Astroparticle Physics
Issue number4
StatePublished - Apr 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics


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