2 research outputs found
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Joint analysis of Dark Energy Survey Year 3 data and CMB lensing from SPT and Planck. II. Cross-correlation measurements and cosmological constraints
Cross-correlations of galaxy positions and galaxy shears with maps of gravitational lensing of the cosmic microwave background (CMB) are sensitive to the distribution of large-scale structure in the Universe. Such cross-correlations are also expected to be immune to some of the systematic effects that complicate correlation measurements internal to galaxy surveys. We present measurements and modeling of the cross-correlations between galaxy positions and galaxy lensing measured in the first three years of data from the Dark Energy Survey with CMB lensing maps derived from a combination of data from the 2500 deg2 SPT-SZ survey conducted with the South Pole Telescope and full-sky data from the Planck satellite. The CMB lensing maps used in this analysis have been constructed in a way that minimizes biases from the thermal Sunyaev Zel'dovich effect, making them well suited for cross-correlation studies. The total signal-to-noise of the cross-correlation measurements is 23.9 (25.7) when using a choice of angular scales optimized for a linear (nonlinear) galaxy bias model. We use the cross-correlation measurements to obtain constraints on cosmological parameters. For our fiducial galaxy sample, which consist of four bins of magnitude-selected galaxies, we find constraints of ωm=0.272-0.052+0.032 and S8σ8ωm/0.3=0.736-0.028+0.032 (ωm=0.245-0.044+0.026 and S8=0.734-0.028+0.035) when assuming linear (nonlinear) galaxy bias in our modeling. Considering only the cross-correlation of galaxy shear with CMB lensing, we find ωm=0.270-0.061+0.043 and S8=0.740-0.029+0.034. Our constraints on S8 are consistent with recent cosmic shear measurements, but lower than the values preferred by primary CMB measurements from Planck
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µ* masses: weak-lensing calibration of the dark energy survey year 1 redMaPPer clusters using stellar masses
We present the weak-lensing mass calibration of the stellar-mass-based µ mass proxy for redMaPPer galaxy clusters in the Dark Energy Survey Year 1. For the first time, we are able to perform a calibration of µ at high redshifts, z > 0.33. In a blinded analysis, we use ~6000 clusters split into 12 subsets spanning the ranges 0.1 = z < 0.65 and µ up to ~5.5 × 1013 M, and infer the average masses of these subsets through modelling of their stacked weak-lensing signal. In our model, we account for the following sources of systematic uncertainty: shear measurement and photometric redshift errors, miscentring, cluster-member contamination of the source sample, deviations from the Navarro-Frenk-White halo profile, halo triaxiality, and projection effects. We use the inferred masses to estimate the joint mass-µz scaling relation given by M200c|µ, z = M0(µ5.16 × 1012 M)Fµ ((1 + z)/1.35)Gz. We find M0 = (1.14 ± 0.07) × 1014 M with Fµ= 0.76 ± 0.06 and Gz = -1.14 ± 0.37. We discuss the use of µ as a complementary mass proxy to the well-studied richness ? for: (i) exploring the regimes of low z, ? < 20 and high ?, z ~ 1; and (ii) testing systematics such as projection effects for applications in cluster cosmology