Effects of baryons on weak lensing peak statistics

Andreas J. Weiss, Aurel Schneider, Raphael Sgier, Tomasz Kacprzak, Adam Amara, Alexandre Refregier

Research output: Contribution to journalArticlepeer-review


Upcoming weak-lensing surveys have the potential to become leading cosmological probes provided all systematic effects are under control. Recently, the ejection of gas due to feedback energy from active galactic nuclei (AGN) has been identified as major source of uncertainty, challenging the success of future weak-lensing probes in terms of cosmology. In this paper we investigate the effects of baryons on the number of weak-lensing peaks in the convergence field. Our analysis is based on full-sky convergence maps constructed via light-cones from N-body simulations, and we rely on the baryonic correction model of [1] to model the baryonic effects on the density field. As a result we find that the baryonic effects strongly depend on the Gaussian smoothing applied to the convergence map. For a DES-like survey setup, a smoothing of θk8 arcmin is sufficient to keep the baryon signal below the expected statistical error. Smaller smoothing scales lead to a significant suppression of high peaks with /> 2, while lower peaks are not affected. The situation is more severe for a Euclid-like setup, where a smoothing of θk16 arcmin is required to keep the baryonic suppression signal below the statistical error. Smaller smoothing scales require a full modelling of baryonic effects since both low and high peaks are strongly affected by baryonic feedback.

Original languageEnglish
Article number011
JournalJournal of Cosmology and Astroparticle Physics
Issue number10
Publication statusPublished - 4 Oct 2019


  • cosmological simulations
  • gravitational lensing
  • power spectrum
  • weak gravitational lensing


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