Bias to CMB lensing measurements from the bispectrum of large-scale structure

Böhm, Vanessa; Schmittfull, Marcel; Sherwin, Blake D.

doi:10.1103/physrevd.94.043519

Cited by 59 publications

(94 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the measurement of κ CMB δ g , we determine the linear bias of the tracer sample, which is needed for the analytic calculation in Equation 13. We verify that κ CMB δ g agrees well with κ CMB δ g (up to a small residual bias consistent with N (3/2) [16]), and thus assess the kSZ-induced bias by comparing κ kSZ CMB δ g to κ CMB δ g . To approximately model the effects of star formation, feedback, and Helium reionization which are present in the simulations, we compare the amplitude of the kSZ power spectrum from the simulations to that expected in our theoretical framework, defining an "effective" f eff free as (C kSZ ) simulations = (f eff free ) 2 (C kSZ ) theory .…”

Section: Numerical Simulations a Validation Of Analytic Formalismmentioning

confidence: 78%

“…In Figures 2 and 3 we show a comparison between max = 4000 and max = 3000, while in our tests we also consider max = 2000. 16 We find that for a CMB-S4 like experiment in cross-correlation with LSST galaxy lensing, the maximum bias at low L goes from ≈ 15% for max = 4000 to 5% and 0.4% when max = 3000 and 2000, respectively. Similarly, the maximum bias to the auto-power spectrum (from Term B only) is reduced from ≈ 8% when max = 4000 to 3% and 0.3% when max = 3000 and 2000, respectively.…”

Section: B Reducing the Reconstruction Maxmentioning

confidence: 95%

“…Such biases can result from both instrumental or astrophysical effects; here, we will focus on the latter. In particular, the observed CMB temperature fluctuations are a sum of the lensed primary fluctuations (which alone would give rise to an unbiased lensing reconstruction, modulo estimator-related complexities [16,37,49]) and several secondary anisotropies due to the interaction (either gravitational or electromagnetic) of CMB photons with late-time structures. These secondary anisotropies include the thermal and kinematic Sunyaev-Zel'dovich (SZ) effects [3][4][5][6], the integrated Sachs-Wolfe (ISW) effect [7], and the nonlinear generalization of the ISW effect known as the Rees-Sciama effect [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Ferraro

Hill

2018

Phys. Rev. D

View full text Add to dashboard Cite

Gravitational lensing of the cosmic microwave background (CMB) is expected to be amongst the most powerful cosmological tools for ongoing and upcoming CMB experiments. In this work, we investigate a bias to CMB lensing reconstruction from temperature anisotropies due to the kinematic Sunyaev-Zel'dovich (kSZ) effect, that is, the Doppler shift of CMB photons induced by Compton-scattering off moving electrons. The kSZ signal yields biases due to both its own intrinsic non-Gaussianity and its non-zero cross-correlation with the CMB lensing field (and other fields that trace the large-scale structure). This kSZ-induced bias affects both the CMB lensing auto-power spectrum and its cross-correlation with low-redshift tracers. Furthermore, it cannot be removed by multifrequency foreground separation techniques because the kSZ effect preserves the blackbody spectrum of the CMB. While statistically negligible for current datasets, we show that it will be important for upcoming surveys, and failure to account for it can lead to large biases in constraints on neutrino masses or the properties of dark energy. For a Stage 4 CMB experiment, the bias can be as large as ≈ 15% or 12% in cross-correlation with LSST galaxy lensing convergence or galaxy overdensity maps, respectively, when the maximum temperature multipole used in the reconstruction is max = 4000, and about half of that when max = 3000. Similarly, we find that the CMB lensing auto-power spectrum can be biased by up to several percent. These biases are many times larger than the expected statistical errors. We validate our analytical predictions with cosmological simulations and present the first complete estimate of secondary-induced CMB lensing biases. The predicted bias is sensitive to the small-scale gas distribution, which is affected by pressure and feedback mechanisms, thus making removal via "bias-hardened" estimators challenging. Reducing max can significantly mitigate the bias at the cost of a decrease in the overall lensing reconstruction signal-tonoise. A bias 1% on large scales requires max 2000, which leads to a reduction in signal-to-noise by a factor of ≈ 3 − 5 for a Stage 4 CMB experiment. Polarization-only reconstruction may be the most robust mitigation strategy.

show abstract

Section: Numerical Simulations a Validation Of Analytic Formalismmentioning

confidence: 78%

Section: B Reducing the Reconstruction Maxmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Ferraro

Hill

2018

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

“…To make good on this promise, however, upcoming lensing measurements will need to control for a plethora of systematics related to beam calibration [14], galactic and extragalactic foregrounds [15][16][17], and non-Gaussian clustering of the lenses [18,19]. In addition, we must have confidence in our modelling of the lensing signal itself.…”

Section: Introductionmentioning

confidence: 99%

Baryonic effects on CMB lensing and neutrino mass constraints

2020

View full text Add to dashboard Cite

Measurements of gravitational lensing of the cosmic microwave background (CMB) hold the promise of yielding unique insights into cosmology at high redshift. Uncertainties due to baryonic effects associated with galaxy formation and evolution, including gas cooling, star formation, and feedback from active galactic nuclei (AGN) and supernovae, have typically been neglected when forecasting the sensitivity of future CMB surveys. In this paper, we determine the impact of these effects using four suites of hydrodynamical simulations which incorporate various prescriptions for baryonic processes, namely OWLS, BAHAMAS, Horizon, and IllustrisTNG. Our analysis shows characteristic power suppressions of several percent in CMB lensing due to baryonic effects, compared to dark-matter only simulations, at experimentally observable angular scales. We investigate the associated bias in the inferred neutrino mass for experiments like the upcoming Simons Observatory and CMB-S4. Depending on the experimental precision and the strength of the baryonic feedback within the simulations, biases in the neutrino mass sum show significant dispersion, ranging from very small to an over-estimation by 1.1σ. We conclude that baryonic effects will likely be non-negligible for a detection of neutrino mass using CMB lensing.

show abstract

“…bias (Böhm et al 2016), which are small at the precision of the current work, and will be neglected.…”

Section: Lensing Autospectrum Estimationmentioning

confidence: 99%

Constraints on Cosmological Parameters from the Angular Power Spectrum of a Combined 2500 deg² SPT-SZ and Planck Gravitational Lensing Map

Simard

Omori

Aylor

et al. 2018

ApJ

View full text Add to dashboard Cite

We report constraints on cosmological parameters from the angular power spectrum of a cosmic microwave background (CMB) gravitational lensing potential map created using temperature data from 2500 deg 2 of South Pole Telescope (SPT) data supplemented with data from Planckin the same sky region, with the statistical power in the combined map primarily from the SPT data. We fit the lensing power spectrum to a model including cold dark matter and a cosmological constant (LCDM), and to models with single-parameter extensions to LCDM. We find constraints that are comparable to and consistent with those found using the full-sky PlanckCMB lensing data, e.g., s W 8 m 0.25 =0.598±0.024 from the lensing data alone with weak priors placed on other parameters. Combining with primary CMB data, we explore single-parameter extensions to LCDM. We find W = k --+ 0.012 0.023 0.021 or n M <0.70 eV at 95% confidence, in good agreement with results including the lensing potential as measured by Planck. We include two parameters that scale the effect of lensing on the CMB: A L , which scales the lensing power spectrum in both the lens reconstruction power and in the smearing of the acoustic peaks, and ff A , which scales only the amplitude of the lensing reconstruction power spectrum. We find ff A ×A L =1.01±0.08 for the lensing map made from combined SPT and Planckdata, indicating that the amount of lensing is in excellent agreement with expectations from the observed CMB angular power spectrum when not including the information from smearing of the acoustic peaks.

show abstract

Bias to CMB lensing measurements from the bispectrum of large-scale structure

Cited by 59 publications

References 68 publications

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Baryonic effects on CMB lensing and neutrino mass constraints

Constraints on Cosmological Parameters from the Angular Power Spectrum of a Combined 2500 deg² SPT-SZ and Planck Gravitational Lensing Map

Contact Info

Product

Resources

About

Bias to CMB lensing measurements from the bispectrum of large-scale structure

Cited by 59 publications

References 68 publications

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Bias to CMB lensing reconstruction from temperature anisotropies due to large-scale galaxy motions

Baryonic effects on CMB lensing and neutrino mass constraints

Constraints on Cosmological Parameters from the Angular Power Spectrum of a Combined 2500 deg2 SPT-SZ and Planck Gravitational Lensing Map

Contact Info

Product

Resources

About

Constraints on Cosmological Parameters from the Angular Power Spectrum of a Combined 2500 deg² SPT-SZ and Planck Gravitational Lensing Map