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The possibly unbiased selection process in surveys of the Sunyaev Zeldovich effect can unveil new populations of galaxy clusters. We performed a weak lensing analysis of the PSZ2LenS sample, i.e. the PSZ2 galaxy clusters detected by the Planck mission in the sky portion covered by the lensing surveys CFHTLenS and RCSLenS. PSZ2LenS consists of 35 clusters and it is a statistically complete and homogeneous subsample of the PSZ2 catalogue. The Planck selected clusters appear to be unbiased tracers of the massive end of the cosmological haloes. The mass concentration relation of the sample is in excellent agreement with predictions from the Lambda cold dark matter model. The stacked lensing signal is detected at 14 sigma significance over the radial range 0.1<R<3.2 Mpc/h, and is well described by the cuspy dark halo models predicted by numerical simulations. We confirmed that Planck estimated masses are biased low by b_SZ= 27+-11(stat)+-8(sys) per cent with respect to weak lensing masses. The bias is higher for the cosmological subsample, b_SZ= 40+-14+-(stat)+-8(sys) per cent.
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We present the cluster mass-richness scaling relation calibrated by a weak lensing analysis of >18000 galaxy cluster candidates in the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). Detected using the 3D-Matched-Filter cluster-finder of Milkeraitis et al., these cluster candidates span a wide range of masses, from the small group scale up to $sim10^{15} M_{odot}$, and redshifts 0.2 $lesssim zlesssim$ 0.9. The total significance of the stacked shear measurement amounts to 54$sigma$. We compare cluster masses determined using weak lensing shear and magnification, finding the measurements in individual richness bins to yield 1$sigma$ compatibility, but with magnification estimates biased low. This first direct mass comparison yields important insights for improving the systematics handling of future lensing magnification work. In addition, we confirm analyses that suggest cluster miscentring has an important effect on the observed 3D-MF halo profiles, and we quantify this by fitting for projected cluster centroid offsets, which are typically $sim$ 0.4 arcmin. We bin the cluster candidates as a function of redshift, finding similar cluster masses and richness across the full range up to $z sim$ 0.9. We measure the 3D-MF mass-richness scaling relation $M_{200} = M_0 (N_{200} / 20)^beta$. We find a normalization $M_0 sim (2.7^{+0.5}_{-0.4}) times 10^{13} M_{odot}$, and a logarithmic slope of $beta sim 1.4 pm 0.1$, both of which are in 1$sigma$ agreement with results from the magnification analysis. We find no evidence for a redshift-dependence of the normalization. The CFHTLenS 3D-MF cluster catalogue is now available at cfhtlens.org.
We present results from the Wendelstein Weak Lensing (WWL) pathfinder project, in which we have observed three intermediate redshift Planck clusters of galaxies with the new 30$times 30$ wide field imager at the 2m Fraunhofer Telescope at Wendelstein Observatory. We investigate the presence of biases in our shear catalogues and estimate their impact on our weak lensing mass estimates. The overall calibration uncertainty depends on the cluster redshift and is below 8.1-15 per cent for $z approx 0.27-0.77$. It will decrease with improvements on the background sample selection and the multiplicative shear bias calibration. We present the first weak lensing mass estimates for PSZ1 G109.88+27.94 and PSZ1 G139.61+24.20, two SZ-selected cluster candidates. Based on Wendelstein colors and SDSS photometry, we find that the redshift of PSZ1 G109.88+27.94 has to be corrected to $z approx 0.77$. We investigate the influence of line-of-sight structures on the weak lensing mass estimates and find upper limits for two groups in each of the fields of PSZ1 G109.88+27.94 and PSZ1 G186.98+38.66. We compare our results to SZ and dynamical mass estimates from the literature, and in the case of PSZ1 G186.98+38.66 to previous weak lensing mass estimates. We conclude that our pathfinder project demonstrates that weak lensing cluster masses can be accurately measured with the 2m Fraunhofer Telescope.
We present the weak lensing analysis of the Wide-Field Imager SZ Cluster of galaxy (WISCy) sample, a set of 12 clusters of galaxies selected for their Sunyaev-Zeldovich (SZ) effect. After developing new and improved methods for background selection and determination of geometric lensing scaling factors from absolute multi-band photometry in cluster fields, we compare the weak lensing mass estimate with public X-ray and SZ data. We find consistency with hydrostatic X-ray masses with no significant bias, no mass dependent bias and less than 20% intrinsic scatter and constrain fgas,500c=0.128+0.029-0.023. We independently calibrate the South Pole Telescope significance-mass relation and find consistency with previous results. The comparison of weak lensing mass and Planck Compton parameters, whether extracted self-consistently with a mass-observable relation (MOR) or using X-ray prior information on cluster size, shows significant discrepancies. The deviations from the MOR strongly correlate with cluster mass and redshift. This could be explained either by a significantly shallower than expected slope of Compton decrement versus mass and a corresponding problem in the previous X-ray based mass calibration, or a size or redshift dependent bias in SZ signal extraction.
In this paper we present results of applying the shear-ratio method to the RCSLenS data. The method takes the ratio of the mean of the weak lensing tangential shear signal about galaxy clusters, averaged over all clusters of the same redshift, in multiple background redshift bins. In taking a ratio the mass-dependency of the shear signal is cancelled-out leaving a statistic that is dependent on the geometric part of the lensing kernel only. We apply this method to 535 clusters and measure a cosmology-independent distance-redshift relation to redshifts z~1. In combination with Planck data the method lifts the degeneracies in the CMB measurements, resulting in cosmological parameter constraints of OmegaM=0.31 +/- 0.10 and w0 = -1.02 +/- 0.37, for a flat wCDM cosmology.
We examine the level of agreement between low redshift weak lensing data and the CMB using measurements from the CFHTLenS and Planck+WMAP polarization. We perform an independent analysis of the CFHTLenS six bin tomography results of Heymans et al. (2013). We extend their systematics treatment and find the cosmological constraints to be relatively robust to the choice of non-linear modeling, extension to the intrinsic alignment model and inclusion of baryons. We find that the 90% confidence contours of CFHTLenS and Planck+WP do not overlap even in the full 6-dimensional parameter space of $Lambda$CDM, so the two datasets are discrepant. Allowing a massive active neutrino or tensor modes does not significantly resolve the disagreement in the full n-dimensional parameter space. Our results differ from some in the literature because we use the full tomographic information in the weak lensing data and marginalize over systematics. We note that adding a sterile neutrino to $Lambda$CDM does bring the 8-dimensional 64% contours to overlap, mainly due to the extra effective number of neutrino species, which we find to be 0.84 $pm$ 0.35 (68%) greater than standard on combining the datasets. We discuss why this is not a completely satisfactory resolution, leaving open the possibility of other new physics or observational systematics as contributing factors. We provide updated cosmology fitting functions for the CFHTLenS constraints and discuss the differences from ones used in the literature.
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