CMB Polarization B-mode Delensing with SPTpol and Herschel

Manzotti, Alessandro; Story, K. T.; Wu, W. L. K.; Austermann, J. E.; Beall, James A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Bock, J. J.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Conley, A.; Crawford, T. M.; Crites, A. T.; Haan, T. de; Dobbs, M.; Dodelson, Scott; Everett, W.; Gallicchio, Jason; George, E. M.; Gilbert, A.; Halverson, N. W.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Holder, Gil; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, Johannes; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; McMahon, Jeff; Meyer, S. S.; Mocanu, L. M.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Vanderlinde, K.; Vieira, J. D.; Viero, Marco P.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zemcov, Michael

doi:10.3847/1538-4357/aa82bb

Cited by 67 publications

(68 citation statements)

References 53 publications

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“…1 of Ref. [36] from the SPT team, using Herschel 500 μm map) shows good consistency 5 over the relevant scales. On this large sky fraction (60%), contamination by galactic dust may reduce somewhat the cross-correlation to the lensing in the GNILC CIB map, and the brown points are slightly lower than expected for clean maps [40,41].…”

Section: Delensing Efficiencymentioning

confidence: 82%

“…Delensing of B-mode polarization has recently been demonstrated on Planck data by remapping the Stokes maps [31], and by the SPT team [36] using a template subtraction method. In both cases, the expected reduction of lensing-like power is approximately set by the squared cross-correlation coefficient of the measured lensing map to the true lensing map, which we call the delensing efficiency: …”

Section: Delensing Efficiencymentioning

confidence: 99%

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Maximum a posteriori CMB lensing reconstruction

2017

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Gravitational lensing of the cosmic microwave background (CMB) is a valuable cosmological signal that correlates to tracers of large-scale structure and acts as a important source of confusion for primordial B-mode polarization. State-of-the-art lensing reconstruction analyses use quadratic estimators, which are easily applicable to data. However, these estimators are known to be suboptimal, in particular for polarization, and large improvements are expected to be possible for high signal-to-noise polarization experiments. We develop a method and numerical code, LensIt, that is able to find efficiently the most probable lensing map, introducing no significant approximations to the lensed CMB likelihood, and applicable to beamed and masked data with inhomogeneous noise. It works by iteratively reconstructing the primordial unlensed CMB using a deflection estimate and its inverse, and removing residual lensing from these maps with quadratic estimator techniques. Roughly linear computational cost is maintained due to fast convergence of iterative searches, combined with the local nature of lensing. The method achieves the maximal improvement in signal to noise expected from analytical considerations on the unmasked parts of the sky. Delensing with this optimal map leads to forecast tensor-to-scalar ratio parameter errors improved by a factor ≃2 compared to the quadratic estimator in a CMB stage IV configuration.

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Section: Delensing Efficiencymentioning

confidence: 82%

Section: Delensing Efficiencymentioning

confidence: 99%

Maximum a posteriori CMB lensing reconstruction

2017

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“…Improved constraints on the presence of an inflationary B-mode signal require delensing, the removal of lensing B-mode power from either the real-space polarization maps or the total BB angular power spectrum. The SPTpol Collaboration recently released a delensing analysis of its own data (Manzotti et al 2017) and is pursuing delensing jointly with the BICEP2/Keck Collaboration, whose observation field overlaps the SPTpol field. Future constraints on inflationary B modes can only benefit from these and other high-resolution measurements of E-mode polarization.…”

Section: Resultsmentioning

confidence: 99%

Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

Henning

Sayre

Reichardt

et al. 2018

ApJ

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209

264

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We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature-E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range ℓ 50 8000  < and detect nine acoustic peaks in the EE spectrum with high signal-to-noise ratio. These measurements are the most sensitive to date of the EE and TE power spectra at ℓ 1050 > and ℓ 1475 > , respectively. The observations cover 500 deg 2 , a fivefold increase in area compared to previous SPTpol analyses, which increases our sensitivity to the photon diffusion damping tail of the CMB power spectra enabling tighter constraints on ΛCDM model extensions. After masking all sources with unpolarized flux 50 > mJy, we place a 95% confidence upper limit on residual polarized point-source power of D ℓ ℓ C 1 2 0.107 K ℓ ℓ 2 p m = + < ( ) at ℓ 3000 = , suggesting that the EE damping

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“…A lens indicates the residual lensing amplitude after delensing the lensing signal. In our analysis, we have taken A lens = 0.5 which is possible to achieve using several delensing algorithms (Simard et al 2015;Sherwin & Schmittfull 2015;Carron et al 2017;Yu et al 2017;Manzotti et al 2017;Millea et al 2017). Aτ denotes the normalization chosen to include or exclude the patchy reionization signal.…”

Section: Contamination To Tensor To Scalar Ratio and Tensor Spectral mentioning

confidence: 99%

Is patchy reionization an obstacle in detecting the primordial gravitational wave signal?

Mukherjee

Paul

Choudhury

2019

Monthly Notices of the Royal Astronomical Society

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The large-scale CMB B-mode polarization is the direct probe to the low frequency primordial gravitational wave signal. However, unambiguous measurement of this signal requires a precise understanding of the possible contamination. One such potential contamination arises from the patchiness in the spatial distribution of free electrons during the epoch of reionization. We estimate the B-mode power spectrum due to patchy reionization using a combination of photon-conserving semi-numerical simulation and analytical calculation, and compare its amplitude with the primordial B-mode signal. For a reionization history which is in agreement with several latest observations, we find that a stronger secondary B-mode polarization signal is produced when the reionization is driven by the sources in massive halos and its amplitude can be comparable to the recombination bump for tensor to scalar ratio (r) 5 × 10 −4 . If contamination from patchy reionization is neglected in the analysis of B-mode polarization data, then for the models of reionization considered in this analysis, we find a maximum bias of about 30% in the value of r = 10 −3 when spatial modes between ∈ [50, 200] are used with a delensing efficiency of 50%. The inferred bias from patchy reionization is not a severe issue for the upcoming ground-based CMB experiment Simons Observatory, but can be a potential source of confusion for proposed CMB experiments which target to detect the value of r < 10 −3 . However, this obstacle can be removed by utilizing the difference in the shape of the power spectrum from the primordial signal. 1 This value changes by about 1-σ with change in the reionization model (Planck Collaboration et al. 2018).

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CMB Polarization B-mode Delensing with SPTpol and Herschel

Cited by 67 publications

References 53 publications

Maximum a posteriori CMB lensing reconstruction

Maximum a posteriori CMB lensing reconstruction

Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

Is patchy reionization an obstacle in detecting the primordial gravitational wave signal?

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