Quantifying the effect of baryon physics on weak lensing tomography

By E. Semboloni, H. Hoekstra, Joop Schaye, Marcel van Daalen, Ian G. McCarthy. 2011

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We use matter power spectra from cosmological hydrodynamic simulations to quantify the effect of baryon physics on the weak gravitational lensing shear signal. The simulations consider a number of processes, such as radiative cooling, star formation, supernovae and feedback from active galactic nuclei (AGN). Van Daalen et al. (2011) used the same simulations to show that baryon physics, in particular the strong feedba ck that is required to solve the overcooling problem, modifies the matter power spectrum on s cales relevant for cosmological weak lensing studies. As a result, the use of power spectra fr om dark matter simulations can lead to significant biases in the inferred cosmological para meters. We show that the typical biases are much larger than the precision with which future missions aim to constrain the dark energy equation of state, w0. For instance, the simulation with AGN feedback, which reproduces X-ray and optical properties of groups of galaxies, gi ves rise to a � 40% bias in w0. We also explore the effect of baryon physics on constraints on m, σ8, the running of the spectral index, the mass of the neutrinos and models of warm dark matter. We demonstrate that the modification of the power spectrum is dominated by groups and clusters of galaxies, the effect of which can be modelled. We consider an approach based on the popular halo model and show that simple modifications can capture the main features of baryonic feedback. Despite its simplicity, we find that our model, when calibrated on the simulations, is able to reduce the bias in w0 to a level comparable to the size of the statistical uncertai nties for a Euclid-like mission. While observations of the gas and stellar fraction s as a function of halo mass can be used to calibrate the model, hydrodynamic simulations will likely still be needed to extend the observed scaling relations down to halo masses of 10 12 h −1 M⊙.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bd79c1bf5fbec4c9dee5fe2a340efe0b16be0988

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Citations in the corpus

Core Cosmology Library: Precision Cosmological Predictions for LSST (2018, background): “…level at scales k & 1 Mpc−1 (van Daalen et al. 2011; Vogelsberger et al. 2014; Hellwing et al. 2016; Springel et al. 2017; Chisari et al. 2018) and can affect the extraction of cosmological parameters (Semboloni et al. 2011, 2013; Mohammed & Seljak 2014; Eifler et al. 2015; Mohammed & Gnedin 2017).”
The Intrinsic Alignment of Galaxies and its Impact on Weak Gravitational Lensing in an Era of Precision Cosmology (2014, background): “The bispectrum has been shown to break degeneracies in the cosmological parameters and to probe additional physics like the non-Gaussianity of large-scale structure (Bernardeau et al., 1997; van Waerbeke et al., 1999; Matarrese et al., 2000; Van Waerbeke et al., 2001; Verde et al., 2001; Takada and ”
KiDS-450: The tomographic weak lensing power spectrum and constraints on cosmological parameters (2017, background): “Feedback from active galactic nuclei, for example, modifies the matter distribution at small scales (e.g. Semboloni et al. 2011; Semboloni, Hoekstra & Schaye 2013), resulting in a modification of the dark matter power spectrum at high multipoles.”
The BAHAMAS project: Calibrated hydrodynamical simulations for large-scale structure cosmology (2016, background): “…fraction (stars+gas, noting that hot gas normally dominates the baryon budget of massive systems) is arguably even more important, since this is a ‘zeroth order’ requirement for ensuring that the feedback effects on the matter distribution are of the correct magnitude (e.g., Semboloni et al. 2011).”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, methodology): “[1072] showed that ignoring the baryonic physics leads to biases in the cosmological parameter estimates that are much larger than the precision of Euclid.”
Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation) (2012, background): “…distribution of source galaxies, and considered power spectrum measurements up to scales ` < 20, 000; we exclude such non-linear scales because poorly-understood effects of baryonic physics are likely to make them difficult to interpret (Semboloni et al. 2011; Kitching, Heavens & Miller 2011).”
CFHTLenS: combined probe cosmological model comparison using 2D weak gravitational lensing (2012, background): “On these scales, ξ− is affected by baryonic physics by less than 5 per cent (Semboloni et al. 2011).”
CFHTLenS: the relation between galaxy dark matter haloes and baryons from weak gravitational lensing (2013, background): “The influence of feedback on the gas distribution in galaxies is a complicated issue which may also affect our results, as discussed in van Daalen et al. (2011) and Semboloni et al. (2011), but it is an effect which we do not attempt to model here.”
Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data (2019, background): “Quantitative estimates of those effects have not yet converged, due to uncertainties in the implementation of sub-grid baryon physics in cosmological hydrodynamical simulations (White 2004; Zhan & Knox 2004; Jing et al. 2006; Semboloni et al. 2011; Osato et al. 2015).”
Cosmic Discordance: Are Planck CMB and CFHTLenS weak lensing measurements out of tune? (2014, methodology): “It has been argued (van Daalen et al. (2011), Semboloni et al. (2011)) that the OWLS ‘AGN’ model, which accounts for the presence of black holes and AGN feedback in dark matter halos using the prescription described in Booth & Schaye (2009), is the most realistic of the different OWLS models, since…”
Cosmological parameter constraints from galaxy-galaxy lensing and galaxy clustering with the SDSS DR7 (2012, background): “…to predict the non-linear power spectrum (e.g., Heitmann et al. 2010) in the absence of modifications due to gas physics, which may be significant on the scales used for typical weak lensing analyses (Zhan & Knox 2004; Jing et al. 2006; Rudd et al. 2008; Zentner et al. 2008; Semboloni et al. 2011).”
KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering (2017, methodology): “HMCODE achieves this through calibration to the OverWhelmingly Large (OWL) hydrodynamical simulations (Schaye et al. 2010; van Daalen et al. 2011; Semboloni et al. 2011; in addition to the Coyote dark matter simulations of Heitmann et al. 2014 and references therein), where the baryonic feedback…”
KiDS+VIKING-450: Cosmic shear tomography with optical and infrared data (2018, background): “This modification has to be A69, page 12 of 30 taken into account to avoid biases in cosmological parameters estimated from cosmic shear (Semboloni et al. 2011).”