LoCuSS: THE SUNYAEV–ZEL'DOVICH EFFECT AND WEAK-LENSING MASS SCALING RELATION

Abstract We forecast the impact of weak lensing (WL) cluster mass calibration on the cosmological constraints from the X-ray selected galaxy cluster counts in the upcoming eROSITA survey. We employ a prototype cosmology pipeline to analyze mock cluster catalogs. Each cluster is sampled from the mass function in a fiducial cosmology and given an eROSITA count rate and redshift, where count rates are modeled using the eROSITA effective area, a typical exposure time, Poisson noise and the scatter and form of the observed X-ray luminosity– and temperature–mass–redshift relations. A subset of clusters have mock shear profiles to mimic either those from DES and HSC or from the future Euclid and LSST surveys. Using a count rate selection, we generate a baseline cluster cosmology catalog that contains 13k clusters over 14,892 deg2 of extragalactic sky. Low mass groups are excluded using raised count rate thresholds at low redshift. Forecast parameter uncertainties for ΩM, σ8 and w are 0.023 (0.016; 0.014), 0.017 (0.012; 0.010), and 0.085 (0.074; 0.071), respectively, when adopting DES+HSC WL (Euclid; LSST), while marginalizing over the sum of the neutrino masses. A degeneracy between the distance–redshift relation and the parameters of the observable–mass scaling relation limits the impact of the WL calibration on the w constraints, but with BAO measurements from DESI an improved determination of w to 0.043 becomes possible. With Planck CMB priors, ΩM (σ8) can be determined to 0.005 (0.007), and the summed neutrino mass limited to ∑mν < 0.241 eV (at 95%). If systematics on the group mass scale can be controlled, the eROSITA group and cluster sample with 43k objects and LSST WL could constrain ΩM and σ8 to 0.007 and w to 0.050.

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Scatter in Sunyaev–Zel’dovich effect scaling relations explained by inter-cluster variance in mass accretion histories

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1712 ◽

2020 ◽

Vol 496 (3) ◽

pp. 2743-2761 ◽

Cited By ~ 1

Author(s):

Sheridan B Green ◽

Han Aung ◽

Daisuke Nagai ◽

Frank C van den Bosch

Keyword(s):

Peak Height ◽

Scaling Relations ◽

Self Similarity ◽

Thermal Pressure ◽

Mass Scaling ◽

Pressure Profiles ◽

Sunyaev Zel'dovich Effect ◽

Mass Assembly ◽

Cluster Variation ◽

Intrinsic Scatter

ABSTRACT X-ray and microwave cluster scaling relations are immensely valuable for cosmological analysis. However, their power is limited by astrophysical systematics that bias mass estimates and introduce additional scatter. Turbulence injected into the intracluster medium via mass assembly contributes substantially to cluster non-thermal pressure support, a significant source of such uncertainties. We use an analytical model to compute the assembly-driven non-thermal pressure profiles of haloes based on Monte Carlo-generated accretion histories. We introduce a fitting function for the average non-thermal pressure fraction profile, which exhibits minimal dependence on redshift at fixed peak height. Using the model, we predict deviations from self-similarity and the intrinsic scatter in the Sunyaev–Zel’dovich effect observable-mass scaling relation (YSZ − M) due solely to inter-cluster variation in mass accretion histories. We study the dependence of YSZ − M on aperture radius, cosmology, redshift, and mass limit. The model predicts $5-9{{\ \rm per\ cent}}$ scatter in YSZ − M at z = 0, increasing as the aperture used to compute YSZ increases from R500c to 5R500c. The predicted scatter lies slightly below that of studies based on non-radiative hydro-simulations, illustrating that assembly history variance is likely responsible for a substantial fraction of scatter in YSZ − M. This should be regarded as a lower bound, which will likely increase with the use of an updated gas density model that incorporates a more realistic response to halo assembly. As redshift increases, YSZ − M deviates more from self-similarity and scatter increases. We show that the YSZ − M residuals correlate strongly with the recent halo mass accretion rate, potentially providing an opportunity to infer the latter.

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