Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

Mirmelstein, Mark; Fabbian, Giulio; Lewis, Antony; Peloton, J.

doi:10.1103/physrevd.103.123540

Cited by 9 publications

(5 citation statements)

References 88 publications

(127 reference statements)

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“…Instead, we subtract a leakage template derived from the measured differential beam map ellipticity. We repeat the analysis without the subtraction and find very small changes in the reconstructed spectra, similar to what has been seen by Mirmelstein et al (2021).…”

Section: Differential Beam Ellipticitysupporting

confidence: 78%

“…For the extreme 10°case, the simulated aa C L shows a very strong signal at low L, while the BB spectrum remains unaffected. We stress that this is not true anymore if we did not calibrate the overall rotation of the maps, and there would be a nonzero mean angle calibration error causing a scale-dependent signal in the distortion field power spectrum (Mirmelstein et al 2021). The curl component of the lensing field ω also detects the rotation field due to the correlation between the α and ω estimators.…”

mentioning

confidence: 96%

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BICEP/Keck. XVII. Line-of-sight Distortion Analysis: Estimates of Gravitational Lensing, Anisotropic Cosmic Birefringence, Patchy Reionization, and Systematic Errors

Collaboration¹,

Ade³

et al. 2023

ApJ

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We present estimates of line-of-sight distortion fields derived from the 95 and 150 GHz data taken by BICEP2, BICEP3, and the Keck Array up to the 2018 observing season, leading to cosmological constraints and a study of instrumental and astrophysical systematics. Cosmological constraints are derived from three of the distortion fields concerning gravitational lensing from large-scale structure, polarization rotation from magnetic fields or an axion-like field, and the screening effect of patchy reionization. We measure an amplitude of the lensing power spectrum A L ϕ ϕ = 0.95 ± 0.20 . We constrain polarization rotation, expressed as the coupling constant of a Chern–Simons electromagnetic term g a γ ≤ 2.6 × 10−2/H I , where H I is the inflationary Hubble parameter, and an amplitude of primordial magnetic fields smoothed over 1 Mpc B 1Mpc ≤ 6.6 nG at 95 GHz. We constrain the rms of optical depth fluctuations in a simple “crinkly surface” model of patchy reionization, finding A τ < 0.19 (2σ) for the coherence scale of L c = 100. We show that all of the distortion fields of the 95 and 150 GHz polarization maps are consistent with simulations including lensed ΛCDM, dust, and noise, with no evidence for instrumental systematics. In some cases, the EB and TB quadratic estimators presented here are more sensitive than our previous map-based null tests at identifying and rejecting spurious B-modes that might arise from instrumental effects. Finally, we verify that the standard deprojection filtering in the BICEP/Keck data processing is effective at removing temperature to polarization leakage.

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Section: Differential Beam Ellipticitysupporting

confidence: 78%

mentioning

confidence: 96%

BICEP/Keck. XVII. Line-of-sight Distortion Analysis: Estimates of Gravitational Lensing, Anisotropic Cosmic Birefringence, Patchy Reionization, and Systematic Errors

Collaboration¹,

Ade³

et al. 2023

ApJ

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“…Finally, we note that a broader, simulated investigation of the impact of instrument systematics on CMB lensing was performed in Mirmelstein et al (2021); although the simulation choices are not an exact match to ACT DR6, it is reassuring that the resulting systematic biases reported there appear negligible at the levels of precision considered in our analysis.…”

Section: Instrumental Systematicsmentioning

confidence: 88%

The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and Its Implications for Structure Growth

Qu,

Sherwin,

Madhavacheril

et al. 2024

ApJ

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We present new measurements of cosmic microwave background (CMB) lensing over 9400 deg2 of the sky. These lensing measurements are derived from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB data set, which consists of five seasons of ACT CMB temperature and polarization observations. We determine the amplitude of the CMB lensing power spectrum at 2.3% precision (43σ significance) using a novel pipeline that minimizes sensitivity to foregrounds and to noise properties. To ensure that our results are robust, we analyze an extensive set of null tests, consistency tests, and systematic error estimates and employ a blinded analysis framework. Our CMB lensing power spectrum measurement provides constraints on the amplitude of cosmic structure that do not depend on Planck or galaxy survey data, thus giving independent information about large-scale structure growth and potential tensions in structure measurements. The baseline spectrum is well fit by a lensing amplitude of A lens = 1.013 ± 0.023 relative to the Planck 2018 CMB power spectra best-fit ΛCDM model and A lens = 1.005 ± 0.023 relative to the ACT DR4 + WMAP best-fit model. From our lensing power spectrum measurement, we derive constraints on the parameter combination S 8 CMBL ≡ σ 8 Ω m / 0.3 0.25 of S 8 CMBL = 0.818 ± 0.022 from ACT DR6 CMB lensing alone and S 8 CMBL = 0.813 ± 0.018 when combining ACT DR6 and Planck NPIPE CMB lensing power spectra. These results are in excellent agreement with ΛCDM model constraints from Planck or ACT DR4 + WMAP CMB power spectrum measurements. Our lensing measurements from redshifts z ∼ 0.5–5 are thus fully consistent with ΛCDM structure growth predictions based on CMB anisotropies probing primarily z ∼ 1100. We find no evidence for a suppression of the amplitude of cosmic structure at low redshifts.

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“…In particular, this work focuses on the initial investigation of the capability of measuring lensing signals with LiteBIRD. Multiple studies have explored the practical issues and developed mitigation techniques for these issues, such as survey boundary and source masking [76][77][78][79][80], inhomogeneous noise [78,81], extragalactic foregrounds [79,[82][83][84][85][86][87][88][89], and instrumental systematics on lensing measurements [90,91]. Among practical concerns on lensing analysis, the Galactic foregrounds are one of the most important issues for LiteBIRD.…”

Section: Jcap06(2024)009mentioning

confidence: 99%

LiteBIRD science goals and forecasts: a full-sky measurement of gravitational lensing of the CMB

Lonappan,

Namikawa,

Piccirilli

et al. 2024

J. Cosmol. Astropart. Phys.

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We explore the capability of measuring lensing signals in LiteBIRD full-sky polarization maps. With a 30 arcmin beam width and an impressively low polarization noise of 2.16 μK-arcmin, LiteBIRD will be able to measure the full-sky polarization of the cosmic microwave background (CMB) very precisely. This unique sensitivity also enables the reconstruction of a nearly full-sky lensing map using only polarization data, even considering its limited capability to capture small-scale CMB anisotropies. In this paper, we investigate the ability to construct a full-sky lensing measurement in the presence of Galactic foregrounds, finding that several possible biases from Galactic foregrounds should be negligible after component separation by harmonic-space internal linear combination. We find that the signal-to-noise ratio of the lensing is approximately 40 using only polarization data measured over 80% of the sky. This achievement is comparable to Planck's recent lensing measurement with both temperature and polarization and represents a four-fold improvement over Planck's polarization-only lensing measurement. The LiteBIRD lensing map will complement the Planck lensing map and provide several opportunities for cross-correlation science, especially in the northern hemisphere.

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Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

Cited by 9 publications

References 88 publications

BICEP/Keck. XVII. Line-of-sight Distortion Analysis: Estimates of Gravitational Lensing, Anisotropic Cosmic Birefringence, Patchy Reionization, and Systematic Errors

BICEP/Keck. XVII. Line-of-sight Distortion Analysis: Estimates of Gravitational Lensing, Anisotropic Cosmic Birefringence, Patchy Reionization, and Systematic Errors

The Atacama Cosmology Telescope: A Measurement of the DR6 CMB Lensing Power Spectrum and Its Implications for Structure Growth

LiteBIRD science goals and forecasts: a full-sky measurement of gravitational lensing of the CMB

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