Abstract:
We use weak-lensing shear measurements to determine the mean mass of optically selected galaxy clusters in Dark Energy Survey Science Verification data. In a blinded analysis, we split the sample of more than 8000 redMaPPer clusters into 15 subsets, spanning ranges in the richness parameter 5 \le λ \le 180 and redshift 0.2 \le z \le 0.8, and fit the averaged mass density contrast profiles with a model that accounts for seven distinct sources of systematic uncertainty: shear measurement and photometric redshift errors; cluster-member contamination; miscentring; deviations from the NFW halo profile; halo triaxiality and line-of-sight projections. We combine the inferred cluster masses to estimate the joint scaling relation between mass, richness and redshift, M(λ ,z) \prop M_0 λ $^F$ (1+z)$^G$. We find M_0 \equiv $\lt$ M_$$200m$$ | λ =30,z=0.5 $$rangle =[ 2.35 \plusmn 0.22 $$(stat)$$ \plusmn 0.12 $$(sys)$$ ] \times 10\^$$14$$ M_$$\sun$$, with F = 1.12 \plusmn 0.20 $$(stat)$$ \plusmn 0.06 $$(sys)$$ and G = 0.18 \plusmn 0.75 $$(stat)$$ \plusmn 0.24 $$(sys)$$. The amplitude of the mass-richness relation is in excellent agreement with the weak-lensing calibration of redMaPPer clusters in SDSS by Simet et al. and with the Saro et al. calibration based on abundance matching of SPT-detected clusters. Our results extend the redshift range over which the mass-richness relation of redMaPPer clusters has been calibrated with weak lensing from z \le 0.3 to z \le 0.8. Calibration uncertainties of shear measurements and photometric redshift estimates dominate our systematic error budget and require substantial improvements for forthcoming studies.
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