28 research outputs found

    The SPTPoL extended cluster survey

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    We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses

    A Measurement of the Cosmic Microwave Background Lensing Potential and Power Spectrum from 500 deg2^2 of SPTpol Temperature and Polarization Data

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    International audienceWe present a measurement of the cosmic microwave background (CMB) lensing potential using 500 deg2^2 of 150 GHz data from the SPTpol receiver on the South Pole Telescope. The lensing potential is reconstructed with signal-to-noise per mode greater than unity at lensing multipoles L250L \lesssim 250, using a quadratic estimator on a combination of CMB temperature and polarization maps. We report measurements of the lensing potential power spectrum in the multipole range of 100<L<2000100< L < 2000 from sets of temperature-only, polarization-only, and minimum-variance estimators. We measure the lensing amplitude by taking the ratio of the measured spectrum to the expected spectrum from the best-fit Λ\LambdaCDM model to the Planck\textit{Planck} 2015 TT+lowP+lensing dataset. For the minimum-variance estimator, we find AMV=0.944±0.058(Stat.)±0.025(Sys.)A_{\rm{MV}} = 0.944 \pm 0.058{\rm (Stat.)}\pm0.025{\rm (Sys.)}; restricting to only polarization data, we find APOL=0.906±0.090(Stat.)±0.040(Sys.)A_{\rm{POL}} = 0.906 \pm 0.090 {\rm (Stat.)} \pm 0.040 {\rm (Sys.)}. Considering statistical uncertainties alone, this is the most precise polarization-only lensing amplitude constraint to date (10.1 σ\sigma), and is more precise than our temperature-only constraint. We perform null tests and consistency checks and find no evidence for significant contamination

    Constraints on Cosmological Parameters from the 500 deg2^2 SPTpol Lensing Power Spectrum

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    International audienceWe present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg2^2 SPTpol survey, the most precise CMB lensing measurement from the ground to date. We fit a flat Λ\LambdaCDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO) as well as primary CMB spectra from Planck and SPTpol. The cosmological constraints based on SPTpol and Planck lensing band powers are in good agreement when analysed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the CMB lensing data alone provide a 4\% constraint on σ8Ωm0.25=0.0593±0.025\sigma_8\Omega_m^{0.25} = 0.0593 \pm 0.025.. Jointly fitting with BAO data, we find σ8=0.779±0.023\sigma_8=0.779 \pm 0.023, Ωm=0.3680.037+0.032\Omega_m = 0.368^{+0.032}_{-0.037}, and H0=72.02.5+2.1kms1Mpc1H_0 = 72.0^{+2.1}_{-2.5}\,\text{km}\,\text{s}^{-1}\,\text{Mpc}^{-1} , up to 2σ2\,\sigma away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTpol and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat Λ\LambdaCDM model. The SPTpol lensing spectrum constrains the spatial curvature to be ΩK=0.0007±0.0025\Omega_K = -0.0007 \pm 0.0025 and the sum of the neutrino masses to be mν<0.23\sum m_{\nu} < 0.23 eV at 95\% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the S/NS/N of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement

    Searching for Anisotropic Cosmic Birefringence with Polarization Data from SPTpol

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    International audienceWe present a search for anisotropic cosmic birefringence in 500  deg2 of southern sky observed at 150 GHz with the SPTpol camera on the South Pole Telescope. We reconstruct a map of cosmic polarization rotation anisotropies using higher-order correlations between the observed cosmic microwave background (CMB) E and B fields. We then measure the angular power spectrum of this map, which is found to be consistent with zero. The nondetection is translated into an upper limit on the amplitude of the scale-invariant cosmic rotation power spectrum, L(L+1)CLαα/2π<0.10×10-4  rad2 (0.033  deg2, 95% C.L.). This upper limit can be used to place constraints on the strength of primordial magnetic fields, B1  Mpc<17  nG (95% C.L.), and on the coupling constant of the Chern-Simons electromagnetic term gaγ<4.0×10-2/HI (95% C.L.), where HI is the inflationary Hubble scale. For the first time, we also cross-correlate the CMB temperature fluctuations with the reconstructed rotation angle map, a signal expected to be nonvanishing in certain theoretical scenarios, and find no detectable signal. We perform a suite of systematics and consistency checks and find no evidence for contamination
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