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تسجيل مستخدم جديدPlanck 2015 results. XV. Gravitational lensing
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We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator we detect lensing at a significance of 5 sigma. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40<L<400 and an associated likelihood for cosmological parameter constraints. We find good agreement between our measurement of the lensing potential power spectrum and that found in the best-fitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of the parameter combination $sigma_8 Omega_m^{0.25} = 0.591pm 0.021$. We combine our determination of the lensing potential with the E-mode polarization also measured by Planck to generate an estimate of the lensing B-mode. We show that this lensing B-mode estimate is correlated with the B-modes observed directly by Planck at the expected level and with a statistical significance of 10 sigma, confirming Plancks sensitivity to this known sky signal. We also correlate our lensing potential estimate with the large-scale temperature anisotropies, detecting a cross-correlation at the 3 sigma level, as expected due to dark energy in the concordance LCDM model.
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We present measurements of the cosmic microwave background (CMB) lensing potential using the final $textit{Planck}$ 2018 temperature and polarization data. We increase the significance of the detection of lensing in the polarization maps from $5,sigm
a$ to $9,sigma$. Combined with temperature, lensing is detected at $40,sigma$. We present an extensive set of tests of the robustness of the lensing-potential power spectrum, and construct a minimum-variance estimator likelihood over lensing multipoles $8 le L le 400$. We find good consistency between lensing constraints and the results from the $textit{Planck}$ CMB power spectra within the $rm{Lambda CDM}$ model. Combined with baryon density and other weak priors, the lensing analysis alone constrains $sigma_8 Omega_{rm m}^{0.25}=0.589pm 0.020$ ($1,sigma$ errors). Also combining with baryon acoustic oscillation (BAO) data, we find tight individual parameter constraints, $sigma_8=0.811pm0.019$, $H_0=67.9_{-1.3}^{+1.2},text{km},text{s}^{-1},rm{Mpc}^{-1}$, and $Omega_{rm m}=0.303^{+0.016}_{-0.018}$. Combining with $textit{Planck}$ CMB power spectrum data, we measure $sigma_8$ to better than $1,%$ precision, finding $sigma_8=0.811pm 0.006$. We find consistency with the lensing results from the Dark Energy Survey, and give combined lensing-only parameter constraints that are tighter than joint results using galaxy clustering. Using $textit{Planck}$ cosmic infrared background (CIB) maps we make a combined estimate of the lensing potential over $60,%$ of the sky with considerably more small-scale signal. We demonstrate delensing of the $textit{Planck}$ power spectra, detecting a maximum removal of $40,%$ of the lensing-induced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance (abridged).
The multi-frequency capability of the Planck satellite provides information both on the integrated history of star formation (via the cosmic infrared background, or CIB) and on the distribution of dark matter (via the lensing effect on the cosmic mic
rowave background, or CMB). The conjunction of these two unique probes allows us to measure directly the connection between dark and luminous matter in the high redshift (1 < z <3) Universe. We use a three-point statistic optimized to detect the correlation between these two tracers. Following a thorough discussion of possible contaminants and a suite of consistency tests, using lens reconstructions at 100, 143 and 217 GHz and CIB measurements at 100-857 GHz, we report the first detection of the correlation between the CIB and CMB lensing. The well matched redshift distribution of these two signals leads to a detection significance with a peak value of 42 sigma at 545 GHz and a correlation as high as 80% across these two tracers. Our full set of multi-frequency measurements (both CIB auto- and CIB-lensing cross-spectra) are consistent with a simple halo-based model, with a characteristic mass scale for the halos hosting CIB sources of log_{10}(M/M_sun) = 10.5 pm 0.6. Leveraging the frequency dependence of our signal, we isolate the high redshift contribution to the CIB, and constrain the star formation rate (SFR) density at z>1. We measure directly the SFR density with around 2 sigma significance for three redshift bins between z=1 and 7, thus opening a new window into the study of the formation of stars at early times.
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overall significance of greater than 25sigma. We use the temperature-gradient correlations induced by lensing to reconstruct a (noisy) map of the CMB lensing potential, which provides an integrated measure of the mass distribution back to the CMB last-scattering surface. Our lensing potential map is significantly correlated with other tracers of mass, a fact which we demonstrate using several representative tracers of large-scale structure. We estimate the power spectrum of the lensing potential, finding generally good agreement with expectations from the best-fitting LCDM model for the Planck temperature power spectrum, showing that this measurement at z=1100 correctly predicts the properties of the lower-redshift, later-time structures which source the lensing potential. When combined with the temperature power spectrum, our measurement provides degeneracy-breaking power for parameter constraints; it improves CMB-alone constraints on curvature by a factor of two and also partly breaks the degeneracy between the amplitude of the primordial perturbation power spectrum and the optical depth to reionization, allowing a measurement of the optical depth to reionization which is independent of large-scale polarization data. Discarding scale information, our measurement corresponds to a 4% constraint on the amplitude of the lensing potential power spectrum, or a 2% constraint on the RMS amplitude of matter fluctuations at z~2.
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